The Musser E0300T Post Insulators (10 Pack) are used on the following Musser keyboard instruments:

M250 Concert Grand Marimba (124 on instrument)
M300 Classic Grand Marimba (124 on instrument)
M44 Combo Vibraphone (88 on instrument)
M46 One-Nighter Vibraphone (88 on instrument)
M46M One-Nighter Vibraphone (88 on instrument)
M48 Pro-Traveler Vibraphone (88 on instrument)
M48S Pro-Traveler Vibraphone (88 on instrument)
M55 Pro-Vibraphone (88 on instrument)
M55G Pro-Vibraphone (88 on instrument)
M75 Century Vibraphone (88 on instrument)
M75LH Century Vibraphone (88 on instrument)