Tair-3S  is supplied with the Zenit foto snaiper camera kit.  This specialty kit comes with the lens, camera, and a rifle stock mount with shoulder butt, pistol grip, and shutter release trigger. This version uses a knob under the barrel to focus (when used with the gun stock) and a spring-loaded diaphragm release activated by the trigger. I found this lens is quite interesting so I pickup one and shared my experience.