What is a lug?

Drum lugs (aka tension casings) attach to the shell at points that correspond to the spacing of eyelets in the counterhoops. A tension rod fits through each eyelet and screws into the lug, which features internal threads that share the same pitch and lead as the tension rod. Several types of lugs are commonly used, including tube lugs (which generally span the length of the shell), low-mass lug casings (which receive a single tension rod in a threaded insert), and double-sided lugs (which accept two facing tension rods).