It has a built-in contact mic and a mic input for using an external contact mic (3.5mm jack). A hand-built external contact mic is also included, along with a power ribbon cable.
If you fancy soldering one yourself (and saving some money in the process) there's also a kit available with all of the parts (including external contact mic and power cable). Build instructions are available online but I'm happy to answer questions and offer guidance if needed. the kit is on a different listing.