The Allen Mainsheet Jammer Dual Arm Swivel Sma & Med Cleat And Block is a dual arm standard height jammer, suitable for both dinghies and keelboats. It is designed for easy access to the central mainsheet and control line, such as the vang, for the trimmer. The jammer is available with or without a 60m Pro-Ratchet Block and features a cold forged bearing system with a ball-locating groove for smooth rotation and prevention of lateral arm movement. The arm can be adjusted to rotate at 180, 220, or 360 degrees. The optimized arm angles allow for easy cleating and uncleating of both lines. It includes a medium aluminium cam cleat with mega pro-lead on the main arm and a small aluminium cam cleat with mega pro-lead on the lower arm. Additionally, the lower arm has two sheaves for efficient rope running from the base to the lower cleat.