What is "rototom"

n. A drum which has no shell

Rototoms are a drum developed by Al Payson and Michael Colgrass, that have no shell and are tuned by rotating. They consist of a single head in a die-cast zinc or aluminum frame. Unlike most other drums, they have a variable definite pitch. Composers are known to write for them as tuned instruments, demanding specific pitches. Rototoms are often used to extend the tom range of a standard drum kit. They were commercialized by the drumhead company Remo.