One of the most common units in Night Vision that is the military and law enforcement standard is the PVS-14. This is a Monocular Night Vision Device (MNVD) that uses a third-generation image intensifier tube, and is primarily manufactured by Litton Industries (Now L-3 Warrior Systems) and ITT Corporation. It is often used “hands free” using a head harness or attached to a combat helmet, but can be used as a weapon’s night sight.
The J-arm is a device that screws to the PVS-14 monocular that allows the user to mount the NVG unit to the NVG mount and helmet. The Wilcox J-arm has a dovetail interface that mates to the Wilcox G24 mount. With this mount you get little-to-no movement between the system.
This makes the system easier to use and work through. Older mounts had a J-arm with a bayonet attachment. The attachment system was easily broken and fell off with minimal pressure on the release button. I recommend staying away from this type of mounting system for obvious reasons.