Vortex 34mm Bubble Level ARCA extension even those which fail to

even those which fail to meet Mil and STANAG specification

8-32 screw (1)

but it will hold its position really well once you set it

Olive Drab Color

Vortex 34mm Bubble Level ARCA extension even those which fail toVORTEX RIFLESCOPE BUBBLE LEVEL FOR 34 MM TUBE Model BL34 The Vortex bubble level helps for the most precise long range shooting. You can easily see the bubble level while on the rifle to ensure that the rifle is perfectly vertical. This will eliminate potential error caused by shooting a canted rifle. This comes into play increasingly as distances get further. The unit mounts quickly and easily to the riflescope tube without any specialty tools.