The DSAS ¼ Thread and Weaver Mount is a directional sound amplification system that uses a cardioid microphone to capture even the faintest sounds from the direction in which it’s pointing. The microphone features a self-contained power supply that is capable of providing uninterrupted operation for up to 300 hours while a wind protection feature significantly reduces background noise caused by air currents; the volume is digitally controlled by small push buttons on the side of the device. Compatible with: NVRS Tactical Riflescopes, NVMT (Sea Wolf) NV Monoculars, Yukon 20-50x50 Spotting Scope, Scout 20x50 Spotting Scope.