Optiparts Optimist Sleeve Pocket Sail - White EX1061WSleeve Sail. Ideal for sailing schools. The mast slides in a sleeve pocket while the sail is loose footed on the boom. Made of strong 3.8oz sailcloth. 5 panel sail without sailbattens, 4 heavily reinforced corners and webbing loops for the boom. Should be used with sleeve mastset EX1052.