The basics The HatsOff Hat Retainer is a modern remedy for retaining the hat's shape. The benefits Constructed of recycled durable polycarbonate plastic. The uses The Hat Retainer is inserted into the hat when the hat is not being worn, and the adjustable handle is given a gentle but firm twist retaining the size of the hat. The bottom line Fits hat sizes 6-3/4″ to 7-3/8.