Like all CASV systems, the CASV-EL relies on "piggy-back" mounting to the top of a "flat-top" M4 upper receiver. This system features a removable lower handguard, which allows the access of an M203 barrel-mounted grenade launcher. The smooth body construction allows multiple rail mounting points, adaptable to any mission needs. Each CASV kit features various lengths of removable rails and mounting hardware.

The CASV-EL is intended to be a "drop-on" rail system for a Carbine-Length gas system that is equipped with a fixed sight-tower/gas block system, as commonly found on most 10.5", 14.5", and some 16" barrels.

Like all CASVs, the CASV-EL relies on the use of the Delta Ring for a more secure mounting point. Vltor does not recommend that any CASV handguard be used without the standard Delta Ring assembly.

This CASV chassis is made entirely of aluminum, with the exception of the stainless steel mounting hardware. After mounted, the CASV-EL adds less than 1lb (13.5 oz without mounted rail sections) to the firearm's overall weight and features a QD sling swivel socket on the left and right sides.