Aluminum alloy precision machining,accurate dimensions. Compatible with Copal No.0 shutter lenses Detailed specifications Flange distance: -18.5mm Inner diameter: 80.5mm,please ensure it can accommodate the lens shutter. Compatible with TC18 model mini view cameras. Compatible with TC1 flagship mini view cameras. Compatible with TCS20 model mini view cameras. Compatible with SWEBO art reproduction platforms. Compatible with all SWEBO mini view camera models,including historical versions.