What is tr500?

Unfortunately, as an AI language model, I cannot provide a detailed answer as to what TR500 is without additional context. TR500 may refer to various things including:

1. TR-500 - A powered air-purifying respirator (PAPR) system designed to protect workers against hazardous particles, including lead, asbestos, and silica dust.

2. TR-5000 - An ergonomic handheld microphone designed for use in professional audio and broadcasting.

3. TR-500 - A model of an electric guitar amplifier produced by the Traynor Amplifier Company in the 1960s.

4. TR-500 Tactical Radio - A two-way radio designed for use in tactical military operations.

Without more context as to what specifically the TR500 is referring to, it's impossible to provide more detailed information on this topic.