Master Lock 911

Lockreviewer’s Take: This is a high end Master Lock with great protection against brute force attacks and shimming while providing a challenge to even seasoned pickers. Recommended for outside use. 

Master Lock says:

The Master Lock No. 911DPF Laminated Padlock features a 2-1/8in (54mm) wide reinforced laminated steel body for maximum strength and reliability. The 5/16in (8mm) diameter shackle is 1-1/8in (29mm) long and made of hardened boron alloy, offering maximum resistance to cutting and sawing. A weatherproof lock body and keyway cover is designed to add protection against moisture, dirt and grime. The 5-pin cylinder prevents picking and the dual ball bearing locking provide maximum resistance against prying and hammering. The Limited Lifetime Warranty provides peace of mind from a brand you can trust.

  • 2-1/8in (54mm) Wide reinforced laminated steel body for superior strength
  • Weatherproof cover and keyway protection
  • Hardened boron alloy shackle for maximum cut resistance
  • 5-pin cylinder for maximum pick resistance
  • Dual ball bearing locking for maximum pry resistance
  • FlexFit™ keyway cover minimizes jamming
  • Removable cylinder – ability to rekey your lock

The first thing that you will notice when trying to open the 911 is that like American Locks, the 911 provides quite a bit of spring tension. As such, you must apply quite a bit of torque. This provides additional protection against potential thieves as it is not immediately apparent to someone picking the lock as to when it actually opens. Additionally, the shackle of the lock is not spring loaded. When you turn the key to open the lock it will not pop open. Rather, you must apply vertical force to the shackle while holding the key to the open position in order to open it.

The keyway is protected with a rubber housing as well as a keyway cover. The shackle is protected by weatherproof lock body extending past the body of the lock to the shackle. This provides excellent water protection as well as the additional benefit of making shims impossible to place. While on the topic of shimming, the dual ball bearing locking mechanism makes shimming impossible and provides additional resistance to brute force attacks such as hammering.

The last attack without getting into picking is whether the lock can withstand a pair of good bolt cutters. 8mm of hardened boron alloy is going to provide quite a bit of a pain for anyone with cheap bolt cutters or even a grinder. Sawing would take quite awhile. I have seen 36” bolt cutters get through 8mm hardened boron in a hurry, but a pair of cutters that big is probably the most conspicuous thing ever. Watch Brute4rce cut on hardened boron below with a 42” set of cutters.

The fact of the matter is that there are very few padlocks, much less absurdly expensive ones, that will completely prevent any break ins. However, the 911 provides great security against brute force attacks at its price point. Below I go over some tips for hobbyists who are trying to tackle the 911. The TL;DR version is that this lock has security pins, the keyway is not easily accessed with picking tools and has high torque resistance. The 911 cannot be rocked, raked or bumped open.

A note to hobbyist pickers: make sure that you are actually applying tension to the keyway. I would recommend using a top of the keyway tension wrench with enough length that you can comfortably hold the lock while picking it. Additionally, the spring tension provides a bit of a problem for pickers. The tension will force many pickers to resort to applying heavy tension to know when the lock has opened, which would be a good strategy in opening a lock if not but for the fact that the 911 has security pins. As such, applying heavy tension to the keyway will only frustrate attempts to pick it resulting in a false set. Rather, the best way to pick this lock is by applying light tension while picking and test with heavy tension after setting each individual pin.

VERDICT: Sitting at $21.63, the Master Lock 911 should be a top contender for your outdoor security needs. I would trust this lock on my shed or garage. 

Master Lock 911






Bypass Rating




Build Quality



  • Affordable
  • Weather Resistant
  • Unshimmable
  • Difficult to Pick


  • Ease of Use

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