No need to say that Noveske Rifleworks is one of the most reliable and reputable rifle manufactures in the world.
The Noveske Rifleworks licensed MadBull free float handguard rail is manufactured for the M4 style Airsoft.
This product is designed for Airsoft and is already blocked the gas pipe tunnel. [Can't be applied on real rifles]
MadBull licensed Noveske handguard rail is made of 6065 Aluminum and machined from an extrusion.
With hard anodized process, our handguard is more durable and looks better than other toy handguards with black color spray paint.

Other features:
Free float tube provides a continuous top rail
Slots on the rail can be timed to slots on the receiver
Unique mounting system

Specifications:
Overall Length: 12.658"

Suitable external barrels:
MadBull M16A2; MadBull M4; MadBull Dissipator 16" and A2; length barrels. (Others length barrel looks fine too.)

Suitable flash suppressor:
Of course, your first choice will be Noveske KX3 and Noveske KFH.