You choose the size and quantity you need from the drop box

Please see second photo for specification sheet

A - (Distance between tip of the longer pin than the shorter pin)

B - (Distance between the top of the round head to the start of the pins)

C - (Outside diameter of round head)

D - Diameter of hole for pins

D1 - (Actual Diameter of pins when closed against each other)

L - (Length of pins only)

So 3.2mm x 40mm would be dmm x Lmm

3.2mm Diameter of hole for pins (Not diameter of the pin) and 40mm length of pins only without round head 

So in theory, you measure the hole you are wanting to fit a split pin through and purchase that size. 
If you have a 3.2mm hole then purchase a 3.2mm split pin. The pin will then be a fraction smaller to fit perfectly. 

A4 316 Stainless steel
Marine grade

We post every day with Royal Mail 24. They do aim for next day but if not next day, 

it shouldn't be too long after that.