Buyers Products One-Piece Cast Coupler Model 0091558Buyers Products One Piece Cast Coupler Model 0091558 The One Piece Cast Coupler from Buyers Products features a spring loaded latch for fast, one hand operation, taking the chore out of coupling your trailer. The latch can be pinned opened for ease of uncoupling. The coupler features a standard 4 1 2 in. bolt pattern for bolting to a trailer nose plate (sold separately). Made of heavy duty cast steel, the coupler can handle loads of 18,000 lb. It