UV Protection Sun Hats Packable Summer Hat Women w/Ponytail Chin Strap 55-61CM Crushable & Packable - you can easily pack and tuck in away in suitcase, great for cruise, outdoor trip, beach vacation and the like. Also it can regain its shape easily, but sometimes you might need steam/ironing machine to reshape it, you can find the instruction from images. Feminine & Fashion - this sun protection hat lookes more stylish than most ladies outdoor hiking or fishing hats. DETACHABLE CHIN STRAP - the neck cord can protect your hat from flying off in wind during travel, gardening or beach vacation. Ponytail Hole - great to pull your bun or ponytail through during summer days. SIZE - Medium best fits for 55-59CM 21.6"-23.2"; Large best fits for 59-61CM 23.2"-24". You can adjust the bowknot at back to find a snug fit.