Top flat picatinny rails, other three sides key hole cutout

Overall Length: 385mm (15.1 inch)

Weight (net): 430g (15.2 ounce)

Inside Dia 46mm (1.8 inch)

Lower rail style with CNC procedure

One piece style more accurate

Upper rail is extended over the barrel nut for a 'no-gap' monolithic look

Light weight in precision

Easy and quick installation

High quality aluminum alloy in durable black matte finish

With tools, 2 pcs 5" detachable picatinny rails and gift box

Fit most model 4 series

Shock proof can be used on real fire calibe

"Key Mod" slots on sides & bottom allow for mounting rail segaments to attach tactical accessories such as vertical gp, laser sights, flashlights, sling mounts, and bi-ods.