Technical Data:
Accessory type: Interchangeable back cover
Configuration/application: Back with Screw Mount, #1/4-28UNF

Dimensions:
Catalogue back-cover drawings show applicable geometry including lug/post/screw/bracket interfaces. Lug-on-center geometry includes Dia.6.5, Dia.12.7, M6x1, 45 deg references and associated millimeter dimensions; flat/post/screw/adjustable constructions follow the illustrated mounting geometry for the selected cover.

Remark:
Most lugged back covers can be rotated 90 deg because they use four retaining screws. 190561 and 137905 have two retaining screws and their lug orientation cannot be changed. Replacing the back cover of a water-proof model voids the water-resistance guarantee where noted by the catalogue.