I am pleased to offer a Pr-Owned Master Spas MAS425 Topside in perfect working condition. The Plug is the Phone Jack Style, see attached photo. I guarantee it to work. Do not purchase it to see if it corrects your problem, then want to send it back if it does not, sorry no returns. Please confirm your sticker on the back of the control say MAS425. This 4 Button Control replaces only that model. Please reach out with any questions prior and after. I am a 40 year Spa Tech and happy to help, to be sure this is what you need or tech support.