Everything you love about the UV3 - Just Bigger! UV3XL has an inside diameter of 41mm compared to UV3's inside diameter of 31mm The Hunting Kit comes with everything you need to start shooting out of the box Everything is pre-installed (including batteries) so all that you have to do is mount it and start shooting The new advanced light has 10 brightness levels, 5 individual LED’s for optimal brightness, auto-off (after 4 minutes), allows you to light up your level, and is 100% waterproof To light up your level, hold the power button for 2 seconds The up-pin is constructed out of a single piece of aircraft-grade aluminum to ensure it is crazy tough Mounts onto Axcel, Shibuya, Sure-Loc, B3, CBE, or any sight that accepts 10-32 threaded rods Over 6hrs of battery life at 80% brightness - takes two cr2025 batteries (can be found anywhere, common size) Easily swap from one lens/hunting cartridge to another depending on what discipline you are shooting Accepts lenses with a diameter of 1.750” Includes: 1 - Housing with a green level installed (aircraft-grade, anodized aluminum) 1- Hunting Cartridge with either a single pin or double pin in 0.010” or 0.019”. For double pin setups: The top pin is green and the bottom pin is red For single pin setups: The single pin is green 1 - UV3XL Light Kit Mounting Bolts & Extra Set Screws 2 - Extra Batteries (cr2025)