This Marlin manufactured military type ring cocking knob and striker assembly is for the model 101 bolt action rimfire rifle and is in very good condition with light wear.  This assembly consists of the military ring cocking knob, cocking knob pin, cocking knob spring, striker, striker pin and striker spring.  (file photo)

Note: Marlin model 101 rimfire rifles with the following year/serial number have been observed with this part: