Performers are expected to bring their own accompaniment (be that in the form of an instrument, or a backing track on their own audio player).
That said, there is a house guitar at all our open mics, in case any performer needs to borrow it.
Depending on which performers are there on any given night, there may be some performers who would be happy to accompany you for your performance.
It's best to speak to them as early as possible (to give them time to learn your song!). Even better, we have a Messenger Group that you can use to ask for help before you even get there!