HeinrichsWeikamp

HeinrichsWeikamp, based in Germany, is a company that produces sports precision instruments for scuba diving including personal dive computers and oxygen partial pressure monitors for diving rebreathers.
Their products: OSTC, OSTC Mk.2, OSTC 2N, OSTC3 and Frog are supported by Subsurface, free software for logging dives authored by Linus Torvalds.