All things being equal, split couplings are easier to install and remove than solid couplings. Order a "No Bore" coupling for machining a custom shaft size "No Bore" split couplings come with a 3/4" to 1-1/4" pilot bore Shown with a male (M Type) pilot In the table below, these are the codes for transmission types: A=Allison, B/W=Borg Warner, C=Capitol, H=Hurth, N=Newage, P=Paragon, TD=Twin Disc, VP=Volvo Penta, Y=Yanmar, ZF=ZF Shaft Range indicated is the available range for that model of coupling Note: in the table, the easiest way to locate the coupling you need is to start with the flange diameter, then shaft size and pilot, etc.