The Steiner SmartClip Adaptor Item #626635 is a precision-engineered interface that allows you to swiftly and securely attach a Nighthunter clip-on thermal module to your riflescope with an approximate 51 mm objective bell outer diameter. The adaptor screws onto the thermal unit and uses a quick-detach cam-lever clamp to lock onto the scope’s front, enabling tool-free installation or removal in the field. Its rugged aluminum body with a black anodized finish delivers durability and stability under demanding conditions, yet remains compact and lightweight so as not to interfere with the optical alignment or handling of your rifle system. Ideal for hunters or tactical shooters who already use a day optic but want to convert to a thermal solution on-demand, this adaptor preserves zero, supports rapid transition between optical and thermal modes, and maintains the optical axis integrity through its secure mounting mechanism. With the 51 mm version you get an expanded fit range for larger-bell scopes, offering increased flexibility without sacrificing reliability. Steiner 51mm Nighthunter Thermal SmartClip Adaptor 626635