FEY part numbers are a combination of the series, style, bore/shaft diameter (D), radial section (RB), ring thickness (RD), and ring material.

A special part number is assigned to ring sizes that have special features like coatings or surface finishes.

BORE					SHAFT
Series	Style	Bore/Shaft Ø	Opposing Ø	Set Thickness	Series	Style	Bore/Shaft Ø	Opposing Ø	Set Thickness
FK5 –	[AS][ASK][ASD][ASKD]	D /	D-(2*RB) x	[RB*3][RB*5][RB*2][RB*3]	FK5	[IS][ISK][ISD][ISKD]	D /	D+(2*RB) x	[RB*2][RB*5][RB*2][RB*3]

The following is an example of a FEY part number:

Style      = ASDK
D           = 150
RB         = 6.0
RD         = 2.0