What is it?

[Gary Watkins]

I got this in a package deal trade. What is it and how do you use it?

[Stan Joyce]

It is exactly that. A Match Box that you can use 2 instruments, Steel and/or Guitar into the same amp. Both inputs are into the Match Box buffering circuit. Can be handy if you play steel and guitar in a band but use one amp.

[Jerry Overstreet]

I think initially the design was during the period when players were using synths. You could put your guitar in one and the synth in the other and blend in the amount of synth you want in the mix...

Of course, the A/B function is another use as Stan writes. I just wish they had included a master volume control.

I have one of those and an old 6PVLC dual action active volume pedal that does the same thing and I use one or the other with a midi rig to switch between them or blend the mix.

[Jack Stoner]

A "Matchbox" provides a constant load on a guitar's pickup and outputs a low impedance signal.
They are designed as the first thing the pickup "sees" and goes between the guitar and Volume Pedal and acts as a buffer for a pot volume pedal input.

If you use a Hilton or Telonics VP its not needed as they provide a constant load to the pickup.