Tapered Opti Mainsheet. FSE's tapered lines feature outstanding properties such as excellent abrasion resistance, extra low stretch, and the use of top-quality polyester from selected suppliers. A specialized line, the Opti Main Sheet is double tapered - thinner at the ends, thicker in the centre where it provides excellent hand grip. The smaller line diameter at the ends reduces friction in blocks and sheaves, for lower physical effort on the sailor. It is constructed of a mix of Dyneema with a polyester yarn for high loads, low stretch and excellent grip. Features: Color - Blue/ Silver. Total Length - 7M. Section Diameters/mm - 6/9/6. Section Lengths/Mm - 1.5/ 2.5/ 3. Note: This sheet is not symmetric, one taper is longer than the other - the long taper runs through the blocks on the boom, the shorter taper runs through the cockpit sole blocks.