Madbull Airsoft 20" Dissipator Outer Barrel

Dissipator M16A2/ A4 length barrel 

What is a dissipator version barrel?
On real dissipator barrels, you can find out two "front sight" adapters.
The first one (close to flash hider) is for "front sight" and the second one (close to the receiver) is for the "Gas Block and Tube" 
By having it this way, you can have a A2 barrel length but the "gas blowback" is still efficient like a regular M4. 

Available handguards in the market:

Regular M16A2/ M16A4 handguards
Other Handguard Rails that fit to M16A2/ M16A4 

Features:
(1) ~1cm length adjustable. Fit most M4 AEGs in the market.
(2) "2" screws to lock the adjustable parts.
(3) Light Aluminum, one piece reinforce barrel. NC processed. 
(4) Best price and quality in the market