For standard length, standard weight AKs/AKMs.
Has vent holes, as found on Chinese AKs and others. See below for details on compatibility

• Clamps rock-solid to barrel for maximum stability and accuracy.
• Replaces the gas tube/upper handguard assembly.
• Includes steel clamps, screws, Allen wrench, and instructions.
• Easy installation: no gunsmithing required.
• Made in U.S.A.

Construction: Solid, one-piece 6061-T6 hard anodized aluminum body.
Rail: Picatinny style (16 slots).
Length: 6.875″

The M2-B has a Picatinny style rail positioned below the iron sight axis, making this the lowest optic mount available for the AK. With a tubular sight mounted low, you will be able to use your optic without a comb riser and still use your regular hold. The system allows for co-witnessing (the ability to use your iron sights right through a 1x sight as a back-up sighting system) when used with a tubular reflex sight mounted low. This heavy duty mount replaces the original steel piston tube and upper handguard, so it adds less than one ounce to the weight of the rifle, making it by far the lightest optic mount installation in the world. The forward positioning of the optic gives you faster, easier and more natural targeting while maintaining your full field of view. Multiple target or moving target engagements, with both eyes open, become second nature.

The mount rarely if ever needs to be removed to clean the rifle, so you need not worry about loss of zero. Since the mount is clamped to the barrel and not jammed in between the gas block and the rear sight block like the original gas tube, several UltiMAK users have reported an improvement in their AKs’ inherent accuracy.