Reel trailers can be used along side coiled tubing units. They are designed to maximize the size and depth of coiled tubing to be spooled on the reel. The typical reel trailer consists of a heavy-duty trailer, a cartridge type reel drum to accommodate various sizes and lengths of coil. A levelwind and counter assembly are included. Reel trailers typically have a basic cabin with controls for reel direction and levelwind override. An injector is typically mounted to the rear of the trailer so the coiled tubing can remain stabbed at all times. Hydraulic power for the reel trailer is typically from an adjacent CTU or hydraulic power pack.