1 x Original Lee Enfield No1 SMLE MkIII MkIII* Ejector Screw 'B' 

Part number 15 in the exploded diagram shown in the 3rd photo. 

British Army Part number BB7033, Excellent condition, new old stock - head and threads are perfect in my opinion, but please bear in mind these are not replica's they are over 70-80+ years old.