Gator GRW-VRM3U 3U Vertical Metal Wall Rack. Gator Rackworks Vertical Mount Metal Wall Racks; 3U. Gator is the leading manufacturer of case solutions for the music and pro audio industries. They offer everything from covers, bags, lightweight cases, plastic cases, roto molded cases and ATA and Tour cases for guitars, amps, keyboards, band, percussion, microphone, racks, mixers, speakers, LCD/Plasma screens, utility, DJ, lighting, projector, laptop, digital recording and more.