Master Lock Company 21KZ 1-3/4...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$24.68
$15.41
Master Lock 21KZ 1-3/4" Laminated Steel Padlock, 5-Pin W27 Cylinder, Zero-Bitted

Master Lock Company 21KZ 1-3/4" Laminated Steel Padlock, 5-Pin W27 Cylinder, Zero-Bitted

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Model: 21KZ-PA

In Stock (leaves warehouse same day if ordered before 3pm ET)

$24.68
$15.41
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Master Lock 21KZ 1-3/4" Laminated Steel Padlock, 5-Pin W27 Cylinder, Zero-Bitted

The Master Lock 21KZ is the industry standard for commercial and industrial physical security. Engineered to withstand severe physical abuse, this padlock features a 1-3/4" (44mm) wide laminated steel body constructed from zinc-plated steel plates for maximum strength, corrosion resistance, and structural integrity. The 15/16" (24mm) tall hardened steel shackle provides exceptional resistance against cutting and sawing, making it a reliable choice for job sites, perimeter gates, and utility facilities.

As a Zero-Bitted (KZ) model, this padlock features a rekeyable 5-pin W27 cylinder that is assembled with zero-bitted pins (all depth cuts are flat/blank). This allows locksmiths and facility managers to quickly and easily key the lock to match their existing master key systems or specific user keyways.

⚠️ Important Ordering Note: Zero-bitted padlocks do not include cut operational keys. They are designed explicitly for locksmiths, institutions, and security personnel who plan to pin the cylinder to an existing key code upon arrival.

Product Features

  • Industrial Laminated Construction: High-tensile laminated steel plates are securely riveted together to offer unmatched resistance against prying, impacts, and physical attacks.

  • Hardened Steel Shackle: Designed with a 5/16" diameter hardened steel shackle that offers elite resistance against bolt cutters and hacksaws.

  • Dual Ball-Bearing Locking Mechanism: Employs a dual-ball locking design that tightly grips both sides of the shackle, preventing shimming, pulling, and hammering bypasses.

  • Zero-Bitted (KZ) Ready: Shipped without operational pinning configurations so you can immediately cut and pin the cylinder to integrate seamlessly into your current facility infrastructure.

  • Commercial-Grade W27 Cylinder: Equipped with a 5-pin, rekeyable W27 keyway layout that provides excellent pick resistance and supports extensive master-keying matrices.

  • Corrosion Protection: Every individual steel plate is treated with a proprietary weather-resistant finish to maximize outdoor service life.

Product Specifications

Specification Details
Manufacturer Master Lock Company
Model / MPN 21KZ
Body Material Laminated Steel (Zinc-Plated)
Body Width 1-3/4" (44 mm)
Shackle Diameter 5/16" (8 mm)
Shackle Clearance (Height) 15/16" (24 mm)
Shackle Clearance (Width) 3/4" (19 mm)
Shackle Material Hardened Steel
Cylinder Type 5-Pin Rekeyable (W27 Keyway)
Keying State Zero-Bitted (KZ) - No Keys Included
Security Grade Commercial Grade

Manufacturer Resources

Product Specs

Subcategory:
Parts & Accessories
Keyed:
Yes
Product Group:
Mechanical Locks
Product Subgroup:
Bored Locksets
Product Type:
Padlocks
Commercial/Residential:
Residential
Product Attribute:
Cylindrical Locks
Tags:
master lock door lock
Product Model:
21KZ
Cylinder Classification:
Conventional Cylinder
Product Category:
Mechanical Locks
Department:
Door Hardware

Master Lock 21KZ-PA – Frequently Asked Questions

1) Does the Master Lock 21KZ padlock come with keys?
No. The 21KZ is the zero-bitted (KZ) version, so the 5-pin W27 cylinder ships with flat, uncut pins and no operational keys. You pin and cut it yourself to an existing key code. If you need a lock that works out of the box, order a keyed-alike or keyed-different 21 instead of the KZ.
2) Will the 21KZ padlock fit into my existing master key system?
That is what it is built for. The rekeyable 5-pin W27 keyway cylinder arrives zero-bitted, so a locksmith can pin it to your facility's change key or master key combination and bring the padlock onto the same system as your doors, provided your system runs the W27 keyway.
3) What size hasp or chain will the Master Lock 21 padlock shackle clear?
The shackle is 5/16 inch diameter hardened steel with 15/16 inch of vertical clearance and 3/4 inch between the legs. So the staple or link you are locking through has to pass a 5/16 inch shackle and sit within a 3/4 inch by 15/16 inch opening. Heavy chain or an oversized hasp staple will not fit.
4) Is a laminated steel padlock like the Master Lock 21 good for outdoor gates?
Laminated construction suits outdoor perimeter and gate use here because each individual steel plate is zinc plated and given a weather-resistant finish before the plates are riveted together, and the shackle is hardened steel. Compared with a solid brass or solid body lock, laminated steel is the cost-effective choice where you want prying and impact resistance across a fleet of gates rather than one high-security opening.
5) Is the cylinder in the Master Lock 21KZ a conventional pin tumbler or a small format interchangeable core?
Conventional pin tumbler. It is a fixed, rekeyable 5-pin W27 cylinder, not an SFIC housing, so you service it by disassembling and repinning rather than by swapping a core with a control key.
6) How wide is the body on the Master Lock 21KZ padlock?
1-3/4 inches (44 mm) across the laminated steel body. That matters when the lock has to sit inside a shrouded hasp or a recessed gate pocket, so measure the pocket opening before you standardize on it.
7) Can the 21KZ padlock be shimmed open?
The locking mechanism uses a dual ball-bearing design that grips both shackle legs, which is what resists shimming, pulling and hammering attacks. It is a two-point hold rather than a single pawl on one leg.
8) How many 21KZ padlocks should a facility buy at once if they are all going on one key?
Buy the full quantity for the key group in one order. Because every 21KZ arrives zero-bitted with no keys, each lock is pinned individually to whatever bitting you assign, so adding more later is no problem at all, just more bench time at the pinning kit. There is no factory key number to match against on a later order.
How fast can I get the Master Lock 21KZ-PA delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Master Lock 21KZ-PA come with a warranty?
Absolutely. The Master Lock 21KZ-PA is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Master Lock 21KZ-PA?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Master Lock 21KZ-PA from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
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