These cars incorporate a mechanism which automatically releases the cams on the leward side of the traveler car when you pull on the windward control line. This allows you to pull the car above the centerline without having to first reach over and release the leward control line. When you tack, the car stays in the same position on the track, and is ready to be pulled to the new windward side. For use with tracks mounted in the cockpit at or near deck level Cars come with modified 150 Cam-Matic cleats built into the control mechanism All Mid-Range and Big Boat cars accept the stand-up spring Control lines cannot be led through turning blocks to a remote location #1637 Mid-Range CB Adapter Kit fits Harken traveler car #s 1624/1625 #2752 Small Boat CB Adapter Kit fits Harken traveler car #s 2722/2727 to 2731/2735/2736