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Master #378 Universal Coupler Lock


  • Fits many 2-5/16" couplers.
  • Adjusts to fit many makes and models.
  • Does NOT fit couplers that do not have a lip such as Bulldog® couplers.
  • Not designed for gooseneck couplers.
  • Each lock comes with 2 keys.

MSRP = $70.81

The big brother to the 377, the Master 378 is a sturdy trailer coupler lock and remains a popular part of Master Lock's towing line. Please don't buy it thinking it will fit your 2-5/16" gooseneck trailer unless you have tried your neighbor's and are sure that it fits!!

NOTE: Master Lock no longer offers this lock in keyed-alike. Sorry. It is not rekeyable.

Add to Cart:

  • Model: MA-378
  • Shipping Weight: 4lbs
  • Manufactured by: Master Lock
  • UPC: 0-71649-21323-6

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