11/20/17 - This is an original WW2 Ku Luger magazine with a serial numbered black bakelite base. The magazine at first appears to be a black widow magazine, with FXO and eagle/37 proofs on the frame, but the serial number on the base indicates this is for a Ku Luger. Ku Lugers were the only known variation to number magazines in this way. The stamp on the base looks factory original. The frame has some light rust but overall is in good condition. The spring is strong and fully functional. Guaranteed original.