Open Front. Made in Japan. A temperature regulating material developed for NASA: Outlast Technology. Outlast technology was originally developed for NASA in the USA. This revolutionary temperature regulating material helps maintain a comfortable temperature range, at the skin surface, in both cold and hot environments. So you're not too hot, not too cold. The crotch area is spacious. 3-dimensional structure. Feel invigorated. Non-restricted Comfort on the Crotch Area!! Japan technology. Three-dimensionally structured for Crotch Area. Japanese patent No.5120755. YARTS original-goods. MSPEC is designed three-dimensionally to fully support from crotch to testicles and to provide the first ever comfortable underwear for men. Upgrade your comfort. The 5 Comforts: 1. Perfect body fit. Perfect support. 2. No shifting to one side. 3. Breathable. Ventilated. 4. Moisture-absorbing. 5. Freedom to move. Movement free. Japan quality. Fabric: Rayon-95%/ Polyurethane-5% Outlast Stretch Tenjiku. Waistband: Toray "quup" Nylon-83% Polyurethane-11% Polyester-6% Width-1.2 inch. It is using excellent moisture absorption Toray "quup " nylon. Select Size=US-Size/JP-Size: (Waist/Waistband. Inch). M=US-S/JP-M: (30-33/26.3). L=US-M/JP-L: (33-36/29). XL=US-L/JP-LL: (36-39/31.8). XXL=US-XL/JP-3L: (39-42/34.5). XXXL=US-XXL/JP-4L: (42-45/37.2). XXXXL=US-XXXL/JP-5L: (45-48/39.9). Note: MSPEC is made with Japanese size. MSPEC Men's Boxer Briefs Outlast is a men's underwear developed by Japanese underwear designer Yasutada Miura to solve his own problems of itching and dermatitis caused by sweat. Both sides of the front body fit closely to the body and act as a partition, so the skin does not come into contact with each other, reducing stuffiness and itching. The front body is large-capacity, so it wraps around you loosely without feeling oppressive. Compared to flat underwear, it is more stable in position, has a sense of freedom, and has excellent breathability.