Today we are going to show you part number 379DAT from Master Lock. This is the coupler lock itself and we are going to use this on a typical coupler. You use a two inch ball. This will either work on 1 7/ 8 inch or two inch also. Simply the ball part goes into the coupler itself. You can latch it down into place like a ball. The whole body slides back into place. Slide it on as far as possible. Take the key, unlatch it. Then it is locked. That part of the coupler is secure. All right with that, that covers our review of part number 379DAT from Master Lock.