I purchased this used from a flea market site two or three years ago. The silver cap-like piece on the top row knob is missing. The operation is not a problem, but there is some crackling in the output jack. Please be sure to read the description regarding transactions in the last image. I am also selling on other sites, so I will prioritize the one that sells first. Multi-functional bass preamp, with 6 knobs to adjust the tone. - Model Name: BASS ATTACK VXL TONE-SHAPER PRE AMP - Brand: Hartke - Number of Knobs: 6 - Number of Switches: 2 Thank you for looking.