Takes place of original USGI rear sight on our housings (Threaded 8-32).
No modifications required for the STG1928.
If you have a semi auto Thompson with 8-32 threaded mount holes this will fit without modifications as well.
Includes base, rail, and screws.
Base shown in-the-white for these photos, but units are shipped with black metal-finish.
The screw mount holes are same as the original Thompson mount location:
.7” (17.8mm) centers on the width and 1.8” (45.72mm) on the front to rear hole centers.
Also fits Umarex Thompson M1A1 air gun "The screw base is perfect, but the screws are different. I used the original screws with little Loctite 242 and is already installed." (From an Umarex owner: Rick S)