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Condition: Used: Very Good
Comment: Minor cosmetic imperfection on top, front or sides of item (affecting less than 1% surface area). Minor cosmetic imperfection on bottom or back of item (affecting less than 1% surface area). Item will come in original packaging. Packaging will be damaged.
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Master Lock 37KA Keyed Alike Armored Trailer Lock with Shackle Guard

3.8 out of 5 stars 159 customer reviews
| 14 answered questions

List Price: $16.24
Price: $13.57 & FREE Shipping on orders over $35. Details
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  • Enter your model number above to make sure this fits.
  • Locks are all keyed alike and it is ideal for securing trailers, cables and chains
  • Armored hardened steel shackle defies cutting
  • 1.562 inch laminated steel body for superior strength
  • 4-pin tumbler cylinder prevents picking
  • Shackle guard protects against bolt cutters and hacksaws
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14 new from $11.29 7 used from $7.34
$13.57 & FREE Shipping on orders over $35. Details In Stock. Ships from and sold by Amazon.com.

Frequently Bought Together

  • Master Lock 37KA Keyed Alike Armored Trailer Lock with Shackle Guard
  • +
  • Trimax UMAX50 Premium Universal 'Solid Hardened Steel' Trailer Lock (fits all couplers)
  • +
  • Camco 44414 Wheel Chock - Pack of 2
Total price: $62.29
Buy the selected items together

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Product Information

Technical Details

Brand Master Lock
Item Weight 10.4 ounces
Product Dimensions 3.9 x 2.2 x 1.3 inches
Item model number 37KA
Manufacturer Part Number 37KA

Additional Information

ASIN B001QK1X5O
Customer Reviews
3.8 out of 5 stars 159 customer reviews

3.8 out of 5 stars
Best Sellers Rank #1,545 in Automotive (See top 100)
#23 in Home Improvement > Hardware > Padlocks & Hasps > Keyed Padlocks
#889 in Home Improvement > Safety & Security
Shipping Weight 10.4 ounces (View shipping rates and policies)
Domestic Shipping This item is also available for shipping to select countries outside the U.S.
International Shipping This item can be shipped to select countries outside of the U.S. Learn More
Date First Available January 23, 2008

Warranty & Support

Warranty, Parts:Parts

Product Description

Master Lock Keyed Alike Armored Trailer Lock With Shackle Guard is ideal for securing trailers, cables and chains. The shackle with guard fits openings 0.5 inch in diameter or larger. The shackle lock is removable to accommodate openings 0.281 inch in diameter. The opening in the center of the lock measures 0.437 inch wide and 0.937 inch tall and has a 1.562 inch laminated steel body for superior strength. It also features a 4-pin tumbler cylinder that helps prevent picking. This shackle guard protects against bolt cutters and hacksaws.

Customer Reviews

Top Customer Reviews

Verified Purchase
I bought 2 locks, they came keyed the same.
They fit both my trailers no probem, see attached pictures.

As another member said they seem to have extra weak points because of the multi point design (hence the 4 stars) but they are snug enough to the trailer where it would be impossible to get a crowbar in there.
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Verified Purchase
this is a very good lock. i decided to purchase it even though some people reviewed that it didnt fit the size hole on their hitch... news flash... this lock comes with a sheath on the lock pin for larger mountings. all you have to do is slide it off for the normal size hole. by the way, the reason i got this one is because my other one has lasted over 20 years already!
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Verified Purchase
I purchased this lock for a small kayak trailer. I drove around locally and I was not able to find a lock like this. As usual amazon carries exactly what I need. It works as advertised. As the pictures attached show there a small sleeve that can be used to fit different trailers. I ended up buying a couple of washers to cover small gaps, just for added security. Keys are sturdy and it comes with 2.
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Verified Purchase
had one for 25 years worked great till i lost it the new one i just got has a better chrome finish
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Verified Purchase
I'm sure I just have the illusion of safety, but I can tell you that this lock fits snugly on my cargo trailer when locked and doesn't expose enough to easily use bolt cutters to get the lock off.
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Verified Purchase
Several of the reviews say how the shaft is too thick, however there is a sheath that you can slide off - very easy with plyers.

However, for my trailer hitch, the hole in the hitch latch for the lock is too close to the hitch ball socket, so the shackle guard gets in the way, therefore it does not work for its intended use for my particular RV trailer.

But, it works just fine for locking other things such as storage shed, etc.
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Verified Purchase
Nice lock for the extra protection. If its too loose in your trailer lock, put some washers in there to prevent prying. Wont defeat other methods of attacks but slowsdown bolt cutters.
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Verified Purchase
This lock is working well for me so far, though I did have to remove the outer sleeve to get it to fit through my Sea-Doo trailer hitch lock hole. Once that sleeve is removed the remaining pin is fairly small and could be broken off easier naturally. It also is a longer pin than needed for my application so I fear someone could get a pair of bolt cutters down in there to cut the lock pin. All of that being said, the lock works as advertised and provides some level of deterrent to running off with my trailer when I am out on the water. ;-) I understand exactly why they made the design decisions that they did. (P.S. I have not tried it, but I am guessing these Master locks would be pretty trivial to pick or use a bump key on)
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Master Lock 37KA Keyed Alike Armored Trailer Lock with Shackle Guard
This item: Master Lock 37KA Keyed Alike Armored Trailer Lock with Shackle Guard
Price: $13.57
Ships from and sold by Amazon.com