Tuning
A drum "hoop" or "rim" may be made of metal, wood, or other material and is used to hold a drumhead against a drum shell, either with bolts through metal "claws" attached directly to a hoop, or bolts through holes in a flanged rim. The bolts, called "tension rods", are screwed into threaded "lugs" attached to the drum shell, in order to tighten and tune the drumhead. A "drum key" is a four sided wrench used to screw the tension rods into the lugs.
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