Inlet & Exhaust Valve Spring Set, for use on BSA models: C15.
O.E.M: 
Inner Spring: 40-0169 / 65-2495
Outer Spring: 40-0168 / 65-2494
Collar: 40-0171
Cup: 40-0170
Collet: 40-0167
Circlip: 40-0134
Supplied: 2 x Inner Spring, 2 x Outer Spring, 1 x Circlip, 4 x Collet, 2 x Collar & 2 x Cup.
Note:
These are a used set, they've been ultrasonically cleaned, and have good compression.