These propeller covers are made from diving suit neoprene. Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range. This material is shock proff, insulated, elastic, waterproof and airtight. Neoprene will conform to the propellers shape and fits different sizes of propellers snugly. 3 or 4 blade propeller covers are available upon request (Minimum Order Quantity 2).