This ZenitCo B-31S upper rail mounts on top of B-30 handguard. Compatible with all AKs, including short barrel ones (exempt for AKS-74U and 9mm Saiga-9). Fully CNC machined. The rail doesn’t interfere with AK iron sights. Battle tested milspec quality, mounts rock solid.
Size is: 200x47x37±5 mm.