The mating pair of the SMH and SFM header series can be used for board stacking or board extension, depending on customer needs. The common board stacking functionality can be achieved when a user mates a SMH male header on top of a SFM female header, as shown in the lower left picture. Parallel board extension can be achieved by using a right angle SMH male header on one end and a right angle SFM female header on the other end, as shown in the top picture. Meanwhile, the bottom right picture shows that perpendicular board extension can be done through a right angle SMH header connected to a straight SFM female header on another board.