The Swarovski tMA Objective Lens Adapter for the tM 35 Thermal Monocular features a solid aluminum construction and is available in the following diameters: 24mm 36mm 42mm 44mm 50mm 52mm 56mm Note: It's important to always use an adapter and never mount the tM 35 directly to the riflescope threads and always make sure there is a distance of at least 2mm between the barrel and the tM 35. Swarovski tMA 56 Thermal Monocular 56mm Objective Lens Adapter for tM 35 Condition A Demo 72311