Octave Key Neck parts fits many Yamaha Sax Necks.

ALL GENIUNE YAMAHA PARTS

Includes Octave Key lever, flat spring, spring screw, lever shaft/screw and pad
Flat spring screw is VERY small and requires a precision screw driver. 

Should also fit the following:

YTS-100
YTS-200AD
YTS-200AD(2)
YTS-200AD(S/N K30000-)
YTS-23
YTS-23(S/N K30000-)
YTS-25
YTS-26
YTS-26S

Yamaha Genuine Part.