An exercise device has two reciprocating arms, each provided with pneumatic or other fluid resistance. The angular orientation of the two arms is limited to one of 0, 45, 90, and 180 degrees. Adjustments are made by loosening a complementary fastener, moving the arms to the desired angular orientation, and then tightening the complementary fastener. Mating projections and recesses prevent movement of the arms relative to each other once the angular position is set.