The EP003K can work with mandolins, but the installation is a little tricky. Firstly, you'll need to remove the tailpiece and the bridge (and use masking tape to mark the bridge position on the soundboard after you install so you can position it correctly. You'll need to bend a coat hanger or nail in order press the piezo and hold it in place against the soundboard until the glue dries). Click HERE for a Youtube Demo video on how to do this with a passive piezo.