Niowasenai can be worn continuously without washing for 4 days; Cool businessman specifications. (Based on our own tests) Niowasenai, so its a good helper for those who wash them. (Prewash and wash separately...Im good? Socks made with thread that inhibits bacterial growth. Maintains effectiveness even after washing. Test Results Price is for a set of 2. 2 Pairs in A4 Envelopes There is no shipping accidents until now.