Dual-Rail Barrel

The Dual-Rail Barrel is a Nerf barrel extension that was released in fall of 2015 under the N-Strike Modulus series.

It comes packaged with the Modulus ECS-10 and can be purchased separately on Amazon.

Details
The Dual-Rail Barrel is a short barrel extension. Unlike other barrel extensions, it features a barrel attachment point, allowing further extensions to be attached to it. It also features two tactical rails: one on top and one underneath the accessory.

Barrel extensions attached to it have poor stability and will wobble around.. This is most likely due to the fact that it does not have a divot built into the front to merge with a barrel extension's locking bead.

Trivia

 * Theoretically, an infinite number of Dual-Rail Barrel accessories could be attached to a blaster.