Rusan Q-R adapter M52x0.75 for Ø41 mm (ARM52-41)

What it is and what it is for
The RUSAN ARM52-41 is a conventional adapter designed to attach night-vision and thermal clip-on devices to a scope objective using an M52x0.75 thread. The ARM52-41 variant is intended for objectives with a 41 mm outer diameter.

Characteristics
Device thread: M52x0.75 (ARM52 system). Variant identifier: 41 mm outer objective diameter. The upper part of the adapter, which receives the NV/thermal device, is made from high-grade aluminium alloy. Recorded weight for the ARM52 family: 0.164 kg. The typical clamping length for most ARM52 adapters is 37 mm.

Compatibility
Compatible with devices and accessories using the M52x0.75 thread within the ARM52 system; the family is used for mounting clip-on and front adapters to scope objectives. Rusan identifies adapters by the objective's outer diameter, not by lens diameter.

Technical notes
For smaller diameter adapters (47 mm or less), including the 41 mm variant, it may be necessary to use an M52x0.75 extension ring if the clip-on's lens protrudes beyond the thread; Rusan cites ERD552 as an example for certain models. The available documentation for the ARM52 family does not list box contents or included fasteners.