Progresco Company
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Choose from our range of industrial drawstring closures and substitute them for knots on most apparel, household, and industrial cord applications, because tying and untying knots has become obsolete. We are one of the original American drawstring closure manufacturers, and we continue to make the B-LOK® line entirely in the US under the following patent numbers:

See the Latest Industrial Drawstring Closures

3132390 4156574 4288891 5440788
Most molded cord closures are now made overseas, as they are generally less expensive. However, the closures do not have the fit and polish as the original, locally-made B-LOK® line, which is now used on higher-end products and proudly advertised as made in the U.S.A. Additionally, instead of having to order at least 10K of our closures overseas, you can order as few as 500 from our authorized local distributors.
6189186 6457214 8321999

Why Choose Our Cord Closures?

  • Easily eliminates unwanted slack on cords from 1/16" to 1/4" diameter
  • Great for seniors, arthritics, and the knot-challenged
  • Proudly manufactured in the USA since 1962
They are stocked in soft elastomeric material in opaque black (but can be special-ordered in many opaque or see-thru colors). Recommended for the dual ends of a drawstring on hats, caps, parkas or other wearing apparel near or about one's face. Now locks stronger yet unlocks easier! To install, orient the lock so that the bridged end of the slit is facing you as in Image a. squeeze the 'ears' inward to open the slit as in Image b. to thread the cords thru. Slide the lock to the desired location and release the ears to lock. Firmly tie off the loose ends of the cords. (To unlock, gently squeeze the ears again and slide the lock away from the load.) 
Recommended Load on the Lock ≤ 5Lbs. 1/16" ≤ Cord Size ≤ 1/8", based on the recommended soft flexible braided tipped cords.

Latest Drawstring Closures

To install, orient the lock so the bridged end of the slit faces you. Squeeze the 'ears' inward to open the slit to thread the cords through. Slide the lock to the desired location and release the ears to lock. Firmly tie off the loose ends of the cords. To unlock, gently squeeze the ears again and slide the lock away from the load. Recommended Load on the Lock ≤ 5lbs. 1/16" ≤ Cord Size ≤ 1/8", based on the recommended soft, flexible braided tipped cords.(NOTE: If you are using EXTRA soft or flexible cords, you can add up to an EXTRA 1/16" to the maximum allowable cord diameter for ALL B-LOK® models.)

B-LOK®-1B P/N 303-0010-1012 (Black) (packed 2500 per carton)

Installation Instructions

B-Lok Logo
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B-LOK®-2L P/N 303-0020-2076 (White) and B-LOK®-2L P/N 303-0020-1818 (Black)

Packed 2500 sets per carton of a given color, these drawstring closures feature a new integral 'shim rib' on the slide that keeps them locked even when the cords are in a no-load mode. Made of Delrin (Acetal) and stocked in opaque black and white colors, it’s highly recommended for the dual ends of a drawstring on flotation vests, small laundry, duffle bags, and miscellaneous wearing apparel.

Installation Instructions

Thread the cords through the cage at the end opposite the tab. Snap the slide into the cage at the tab end. Slide the lock against the load and push the slide inward to lock. Firmly tie the ends of the cord together. To unlock, hold the cage with one hand, pull the slide outward with the other, and slide the whole lock away from the load as desired. Recommended Load on the Lock: ≤ 25lbs.1/16" ≤ Cord Size ≤ 1/8", based on the recommended soft, flexible braided cords.

B-LOK®-3C P/N 303-0030-6015 (White) and B-LOK®-3C P/N 303-0030-6025 (Black)

Packed 2500 sets per carton of a given color with pat. no. 8321999, these closures have self-lock features and stays that way even with surrounding tension. They have a lower center-of-gravity appearance that prevents confusion with inferior knockoffs. The spring arms with squeeze tabs and narrow shaft allow for threading on new cords without removing the slide from the cage. The extra rib added to the cage notches at the bottom so the cage will lie flat when the cords are under tension. Stocked in opaque black or white polypro, these closures are recommended for the dual ends of a drawstring on larger bags, including laundry, duffel, and sleeping models, as tie-downs for luggage, ladders, and other cargo, soccer ball tethers, etc. The end of the slide can also accommodate a lanyard for remote opening or discharge.

Installation Instructions

Thread the cords through the throat of the cage. Snap the slide into the cage. To enhance the self-locking action and keep the cords in the locked position even without tension in the cords, optionally thread the cords through the side channels provided in the new ring pull. Recommended Load on the Lock: ≤ 35lbs. 1/8" ≤ Cord Size ≤ 3/16", based on the recommended soft, flexible braided cords.

B-LOK®-4A

B-LOK®-4A has been discontinued. Please use B-LOK®- 1B.

B-LOK®-5CHD

Considered the world’s best FIBC cord lock for higher-end flexible intermediate bulk containers, the B-LOK®-5CHD comes packed at 500 sets per carton under pat. no. 8321999. It self-locks and stays that way even without tension. The lower center-of-gravity appearance helps avoid confusion with the inferior knockoffs, while its spring arms with squeeze tabs and narrow shaft allow for re-threading on new cords without removing the slide from the cage. The additional rib on the cage plus beefed-up notches at the bottom so the cage lies flat when the cords are under tension. Essentially, the B-LOK®-5CHD is a larger, heavier-duty version of the -3C, but stocked in opaque UV-stabilized Manila Polypro per carton. This is also the latest version of the original B-LOK-5 drawstring cord closure, as it can resist breaking under prolonged high-load and high-heat conditions better than all the previous models, and is less likely to unlock accidentally.

Installation Instructions

This closure is installed the same way as the -3C model. Keep in mind that optionally threading the cords through the side channels in the ring pull further aids the self-locking action and keeps the cords in the locked position even without tension in the cords. The B-LOK®-5CHD is recommended for large bulk bags, rigging for sailboats, tents, trees, and other heavy-duty industrial applications. As before, the end of its slide can accommodate a lanyard for remote opening. Recommended Load on the Lock: ≤ 75lbs. 3/16" ≤ Cord Size ≤ 1/4", based on the recommended soft, flexible braided cords.

B-LOK®-6A P/N 303-0060-1618 (BLACK)

Packed at 100 units per carton, this is the lightweight, low-cost substitute for a metal postal rope lock. It’s the best plastic tamper-resistant rope lock for mail, bank, and courier bags. Stocked in black (acetal), the single leaf springs of the B-LOK®-6A P/N 303-0060-1618 have been replaced by sawtooth springs with virtually no permanent set. Side notches are also added at the bottom sides of the cage so it will lie flat against the load when there is tension in the cords. The original drawstring bags are beginning to make a comeback against the current trend of zipper bags, which users are discovering have to be thrown out when the zippers are damaged in normal shipping and handling procedures. Drawstrings, meanwhile, can be easily replaced without having to throw away the entire bag. Thus, the sooner you settle for the inexpensive plastic B-LOK-6A, the sooner you will begin saving.


Installation Instructions

To install, start with the slide completely separated from the cage. Thread the cords through the cage, then insert the slide in the cage to the intermediate position, which will be confirmed by a 'clicking' sound.

Operation Instructions

To operate, slip the standard-size address label (1"x3.3") into the recessed area of the cage. Holding the cords firmly in one hand, use the other to slide the lock all the way inward to completely close the mouth of the bag, then push the slide all the way into the cage. Insert the desired common padlock or security seal. To unlock and loosen, remove the padlock or security seal and flick the head of the slide outward with your thumb. Recommended Load on the Lock: ≤ 75lbs. Cord Size: = 3/16", based on braided cotton cord currently used by the USPS.
Made In USA
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B-LOK®-5CHD Internal View
B-LOK®-5CHD Frontal View
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Miscellaneous B-LOK® Notes: 1.) It is the responsibility of the end using customer to determine the suitability of these locks for the specific application. Progresco's liability shall be limited to replacing parts due to faulty materials or workmanship. 2.) If you are interested in switching to the ideal recommended soft, pre-cut, tip chords at likely a lower cost then you are currently paying for cords that you are now hot-cutting or tying knots in, then we suggest you contact Bill Magill of Lea & Sachs at 877 296-7500 (toll free). In particular, we recommend style #4527 with 3/8" tips for the B-Lok - 2L & 3C, style #4645 with 3/4" tips for the B-Lok - 1B, and style #4531 - M with 1/2" tips for the B-Lok - 5CHD. These are normally provided in White Polyester, but you can specify Polypropylene, Nylon, etc. In most any common color. 3.) B-LOK® is a U.S. registered trademark of Progresco for cord locks. Only Progresco is authorized to market and sell cord locks bearing or associated with the B-LOK® trademark in any form and any marks confusingly similar to the B-LOK® mark, including, but not limited to, B-Lock 3, B-Loc 3, B-Lock 5, and/or B-Loc 5. Thus, any such cord locks, either alone or installed on or in conjunction with other goods, marketed or sold by anyone other than Progresco and identified as bearing the B-LOK® trademark or any marks confusingly similar to the B-LOK® mark, that are sold or imported into the U.S. are subject to confiscation at U.S. Customs. Since Progresco has discontinued manufacturing and selling the original B-LOK® 3A and B-LOK® 5 cord locks several years ago, new cord locks being made and sold under these appellations are counterfeits and thus also subject to confiscation at U.S. Customs.
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