Between the transparent substrate 2 and the light source portion 4, the light diffusion film 20 to diffuse the light as the light diffusion layer is interposed. The guitar slide holder can be releasably attached to a guitar strap so as to be easily accessed by the guitarist. When the failure rate exceeds a threshold, a maintenance ticket is generated automatically. The theft prevention system can include a filter for attenuating irrelevant acceleration frequencies and isolating those representative of theft, and comparison hardwaresoftware for determining whether the detected acceleration matches a known acceleration profile characteristic of theft. If the instance identifications associated with the service agent have been deleted, a Remote Procedure Call protocol command is sent to the service agent.