Concept2 is a manufacturer of rowing equipment. They are probably most well known for their inoor rowing machine, which can be found in most gyms and are considered the standard training machine for world-class rowers. They also manufacture oars for sculling and sweep rowing (under the name Dreissigacker). Their products are shipped worldwide. Ironically, competitive rowers never refer to the machine as an "indoor rower" but use the older name of "erg" (short for ergometer).