Master Lock No 141

= Master Lock No. 141 =

The No. 141 is a pin-tumbler padlock made by Master Lock. The No. 141 is a 40mm wide solid body padlock with a black plastic cover with the word "Master" inlaid in silver. The plug is made of brass and does not contain any security pins. The shackle has a diameter of 6mm, and a length of either 22mm or 38mm.

Principles of operation

 * See also Pin-tumbler (Principles of Operation)

The No. 141 can only be opened by rotating the plug clockwise.

Disassembly instructions
The No. 141 cannot be disassembled non-destructively; to disassemble it the lock must be sawed in half. The lock is nonfunctional once disassembled because the padlock body acts as the cylinder for the lock.

Vulnerabilities
The 141's low pin-tumbler count, at 4 pins, and poor manufacturing tolerances allows it to be easily picked by low skill attackers. It is commonly used in locksport groups as an introductory lock for beginners to learn.

The 14x series is vulnerable to overlift attacks, where the entire pin stack can be lifted with a comb pick into the driver's pin chamber and allowing plug rotation.

The No. 141 may be vulnerable to one or more of the following:


 * Lockpicking
 * Key bumping
 * Impressioning
 * Bypass
 * Destructive entry