This Japanese manufactured rear sight assembly is for the Type 99 Arisaka bolt action rifle in 7.7 caliber and is in good condition exhibiting a mixture of thinning original blue finish with a brown patina and having many spots of older rust. The rear sight slide has the aircraft arms. The spring screw and mounting screw are missing.  (file photo)

Note: Japanese Type 99 Arisaka bolt action rifles with the following arsenals and / or serial numbers have been observed with this part: 16866 & 21908