NiSi 40.5mm Adapter for M75 75mm Filter SystemNiSi NIP M75 AD 40. 5 40. 5mm Adapter for M75 75mm Filter System The NiSi 40. 5mm adapter for NiSi M75 75mm Filter System allows the 67mm filter holder adapter ring included with a NiSi M75 75mm Filter Holder Kit to be used on a lens with 40. 5mm front filter threads. It features an aluminum alloy construction for durability while remaining lightweight. Technical Specifications Compatible Lenses Any lens with a 40. 5mm standard filter thread