Rear sight for the "Santa Fe Jungle Carbine". This is a No.1 Enfield which slightly resembles a No.5 Enfield.
Screw not included.
Actual mounting screw was a shortened 1903 Springfield front band screw. Second photo shows the placement of spring.
These are original used parts in Good condition.
Expect mild to heavy finish wear, scratches and dings, grease and grime.