The FHR Vision Advantage Plus Sliding Tether Set is FIA 8858-2010 approved and allows a greater freedom of movement in racing conditions while maintaining the safety and performance of an FHR system. The sliding tether allows head movement for unlimited side to side vision, can be retro-fitted to any FHR device ever made as it contains everything you need to convert one FHR device (tether carriers, tether, screws and full instructions included).The Vision Advantage Plus sliding tethers are available in three different lengths. Recommended length is 18 which comes as standard on all new Medium and Large FHR devices. For users with open face helmets where the clips are located further back on the helmet or those looking for a slightly shorter version SCHROTH offers the 17 version. In addition a 19 version is available for use with XL FHR devices.