Comparison : Item # 4471-4, 1/4 " Female Pipe Thread Size Steel Coupler Pin
Item # 4471-6, 3/8 " Female Pipe Thread Size Steel Coupler Pin
Item # 4472-4, 1/4 " Female Pipe Thread Size Steel Coupler Pin
Item # 4472-6, 3/8 " Female Pipe Thread Size Steel Coupler Pin