A tension rod is a straight, threaded screw with a flat tip and a square head, which threads through the eyelets of a counterhoop and into receiver nuts inside a drum lug. Using a drum key to turn a tension rod clockwise will compress the counterhoop onto the shell’s bearing edge, thereby tightening the drumhead. Turning the tension rod counterclockwise will loosen the head. Most drum companies use tension rods and lug receiver nuts that employ a coarse industry-standard pitch (the distance from the crest of one thread to the next) except for DW and Sonor, which employ tension rods with a finer pitch. Also, the heads of some Sonor tension rods are slotted, and marry with an internal wedge inside Sonor’s drum key, which works similarly to a screwdriver.