*The Kinno Scuba animal cartoon characterized diving hood is is made with 3-millimeter Premium Neoprene,it features a smart design that allows air bubbles to escape without causing water entry and that can conform to your specific anatomy. The hood's integrated air vent allows bubbles to escape through the top of the hood, preventing ballooning without promoting water exchange. Smooth neoprene in excellent shape and right size with no fluff forming unlike poorer quality ones. Good seal, no mushroom head and will warm my head Technical Details : Apparel Occasion and Lifestyle athletic water-sports swimming all-weather Fabric Type neoprene Material Type neoprene Sport Type Diving About Size The Kinno Scuba hoods totally has 3 size for selection,Medium, Large and Free size. Medium Size is suitable for head size within 58cm(23.2inch); Large Size is suitable for head size bigger than 58cm(23.0inch). The Free Szie is suitable for head size with no limitation. P.S. Too flabby the hood will effect the warm-keeping underwater. Measuring heads for hood sizes Head column: If you measure the head in the same way a headband would fit around it, the number you come up with is what you would look up. About Wrinkles The diving material in dry condition when fold it there will have wrinkles. They will be flat itself when underwater for diving material will expand in water. About Flavor The hood is sealed by glue before sewing up, so there will be remaining glue flavor. Put the hood in air for ventilation for 2days or after use in water, the flavor will fade away. About Maintenance Do not use chemical reagent like laundry detergent or powder to clean the hood. Just clean with clear water and naturally dry it in shade.