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7/16” Hardened Stainless Steel Shackle – Aluminum Body Padlock

  • 1"
  • 2-1/2"



If you’re looking for high security in a shackle that is almost impossible to cut with bolt cutters, the UCS-4A is the best padlock you can buy. The 2-1/4″ aluminum body along with the 7/16″ thick shackle truly make this padlock the toughest padlock on the market. If your application allows you to use a 7/16″ shackle, the best choice for true security is the UCS-4A, you won’t be disappointed.

What is UCS?

PACLOCK’s Universal Cylinder System (UCS) makes it easy for you to key different padlock styles alike to give you full customization of your lock setup. With UCS, you can expand your system to an unlimited number of locks with only one key, or even start your own master or grand master lock system. All brass, aluminum and stainless steel components render all UCS padlocks rustproof. 6-Pin technology (when most locks only have 4 pins) provides over 20,000 unique key codes and makes duplicate key combinations uncommon, meaning your key number is virtually unique to you.

Stainless steel spool and serrated security pins make the lock pick, bump and drill resistant. Dual ball bearing locking and other security features make the lock bypass and shim proof. Change to a long length shackle in seconds using PACLOCKs modular UCS shackles. CNC machined for U.S. precision and reliability, both the cylinder and lock body exceeds plus or minus 0.003 tolerances for repeatable quality.


  • Medium-duty 7/16 in. diameter shackle for a variety of applications
  • Industry-first hardened stainless steel shackle is tough to cut and weather resistant
  • Buy American Act Compliant
  • All brass, aluminum, and stainless steel rust-proof components
  • Made in the USA with Global Components
  • Pick, bump, and drill resistant cylinder technology with stainless steel components and 20,000 different keys available
  • CNC machined for precision U.S. quality and reliability
  • Includes the PAC-BAND™, a silicone cover to protect the cylinder from the elements


Features & Options


  • Universal Cylinder System
  • Available in PACLOCK Blue
  • Assembled in the U.S.
  • Hardened Stainless Steel Shackle
  • Solid brass actuator
  • 6-Pin, True-Security Serrated, and Spool Top Pins
  • Dual Ball-Bearing Toe and Heel Locking Design
  • Keys included: 2
  • Country of origin: USA
  • TAA compliant

Available Options

  • Keyed-Alike, Master-Keyed, or Grand Master-Keyed
  • Hardened Stainless Steel Shackle 1″, 2-1/2″

Specs & Dimensions


  • Body material: Aluminum
  • Body width: 2-1/4″
  • Shackle material: Hardened Stainless Steel
  • Shackle diameter: 7/16″
  • Shackle height (closed): 1″, 2-1/2″
  • Shackle spread (inside): 25/32″
  • Cylinder: UCS 6-Pin True Security Cylinder