The Swarovski tMA Objective Lens Adapter for the tM 35 Thermal Monocular features a solid aluminum construction and is available in the following diameters:24mm36mm42mm44mm50mm52mm56mmNote: 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 52 dS Thermal Monocular 52mm Objective Lens Adapter for tM 35 72312 - Excellent Condition 9034