These are absolutely sexy and stunning and can be worn as underwear or swimwear. Neptio brand (registered trademark).They are unlined and provide open side access and clips that can be undone (plastic). Contrast colors. The elastic waist provides plenty of stretch so sizing is normal on these with room for error. Palm Spring style swimwear for men. Micro Poly and Spandex blend Small 27"-30", Medium 31"-34", Large 35"-39", XL 39-43"