27 mm Midrange CB (Captive Ball) Track is made of tough 6061-T6 aluminum that is Hardcote-anodized black with Teflon impregnation for durability and easy bearing movement. It comes in both low- and high-beam configurations.Use standard low-beam track when it is supported at each fastener hole. This Retrofit low-beam track is designed as a direct replacement for older track designs (like Nicro Fico) with 4" spaces between fastener holes; first hole is 2" from the end of the track.Use high-beam track when it must span a cockpit or other unsupported area. Refer to the 27 mm High-Beam Track Spanning Chart on our website for details. Maximum mainsail area for 27 mm track ranges from 14.9 m (160 ft) for multi-hulls with mid-boom sheeting using standard cars, to 32.5 m (350 ft) for lightweight mono-hulls with end boom sheeting When end controls are not used, add HAR #E2700 or #1523 endstops to absorb shock loads (sold separately) When end controls assemblies are used, trim caps can be used to finish the track ends Splice links (#1619) help align low beam track sections during installation Fasteners: 5/16"FH low-beam track; 1/4"HH high-beam track; 1/4"FH retrofit track Can be bent to your specifications, please call for details Minimum bend radius for both Low- and High-Beam R27 Track: 2.44m (8ft) for standard/short cars; 2.73m (9 ft) for HL/long cars Note: Due to its length, track over 3.5m (9 ft) in length must be shipped via truck or air freight