The inner lining is made of 92% polyester and 8% spandex, very good breathability can keep your sports comfortable, the compression lining of the boxer swimming trunks can protect your skin, and can also prevent the outer pants from sticking to the skin when the shorts are soaked. 92% Polyester, 8% Elastane Machine Wash Fastening: Drawstring Boxer stretch Sleeveless Arcweg370954FD Quick Dry and Stretch Fabric:This swimwear made out of 4-way stretch polyester fabric, with water repellent technology, dry fast and superior light weight fabric. Due to water-repellent feature, It can easily get up from the water, dry quickly from the wet, suitable for all water sports or holiday beach activities. Elastic Waistband with Drawstring: The swim trunks combined an elastic waistband and adjustable drawstring, you can flexibly adjust your waistline to make sure your beach shorts will not slip down so that you can enjoy a better beach time. Wear On Multiple Occasions: Slightly elastic material and small slit, Free movement during sport, Ideal for various outdoor and indoor sports, beach, surfing, swimming and also suitable for aerobic exercise such as gyms, lined shorts also have good sweat-absorbing function, mens swim trunks which is a great choice for sports and fitness. Size suggestion: If you usually wear M(UK), please choose M. If you need more information, see the size chart in description."