Pearl created several drum products, such as shells in the 1970s that were made of wood with a fiber-glass lining. There was also a shell made of a composite called "Phenolic." Additionally, Pearl combined roto-toms and these Phenolic shells to create the Vari-Pitch line of drums. Other early innovations included shells that were slightly undersized, so that the drum head would extend over the edges, much like a gong drum. Pearl manufactured seamless, extruded acrylic shells that were different from the tabbed-and-seamed Vistalite shells used by Ludwig. Pearl also developed the hinged tube tom-arm, a design widely copied by many other drum manufacturers.