The BBE Opto Stomp Optical Compressor serves up vintage-voiced compression in a tanky, durable metal enclosure with a simple interface of two knobs for threshold and output. Designed to add a nice bite to your existing tone while remaining transparent so as to retain the clarity of your rig, this stompbox's basis in "soft-knee" compression makes it an ideal candidate not only for guitar, but bass, keys, and acoustic instruments with a pickup.