Hitech 85 Standard Adapter Ring. These machine crafted aluminium rings are designed to fit onto the lens enabling a Hitech 85 Filter Holder to slide in place. They are available as front screw adaptors (the standard and most commonly used) and bayonet adaptors in a variety of sizes. Front screw adaptors are the standard range of adaptors which fit directly onto the lens. They all step up to a standard size. Bayonet adaptor rings (e.g. B60) are designed to fit bayonet lenses such as Hasselblad.