The bases and cam arms of these durable track ends are machined from a single piece of aluminum. Compact, high-strength Carbo Airblock components are combined with Micro Carbo-Cam cleats to keep traveler weight minimal. An integral deadend in each unit provides termination for control lines, as necessary. If you use the traveler controls from an angled position, add the #476 X-Treme Angle Fairlead to the cam cleats. You can color code the cleats using #424 Top-Mount Fairleads, or #431 Cam Caps, each available in 5 colors. (See separate entries.)If traveler controls are not used, you can help prevent shock-loading your rig by using a pair of #2755 Pinstops on track with drilled pinstop holes, to localize the traveler position.ESP end controls are value-oriented options for the installation of 2:1 to 5:1 systems. Designed for strength and durability, controls feature axle bearing sheaves with sideload ball bearings. Harken purchase recommendations when using traveler control blocks on smaller boats: Use a 2:1 purchase for boats with sail area under 140 ft (13 m) Use a 3:1 purchase for boats with sail area from 140 ft to 175 ft (13 m to 16 m) Use a 4:1 purchase for boats with sail area from 175 ft to 190 ft (16 m to 18 m)