IFMC. Hot Spring Socks have been made "Stay on your feet" by IFMC, a technology focused on hot spring therapy. Heats like foot bath, so you dont need to wear them over again. It is also recommended for those who do not like tightening without rubber socks. It can be used with confidence even for those who are prone to swelling feet. Available in 4 colors. IFMC. is a favorite of many athletes.