The RapidStrike CS-18 is an automatic blaster. It features five tactical rails: one on the carrying handle, one on top, one underneath, and one on each side of the blaster. It also has an integrated, adjustable shoulder stock, a small flip-up iron sight on top of the barrel, and four strap points: one on the end of the handle, two on the end of the tactical rail, and one above the muzzle. Like other N-Strike Elite blasters, its clip release button is located in front of the firing trigger and its acceleration trigger.
The barrel of the RapidStrike is rifled, similar to the Retaliator barrel extension. It is compatible with barrel extensions. Due to the barrel extension connector being a separate piece of plastic from the main barrel, it can loosen up, resulting in a loose fitting barrel extension.