Balboa Water Group 51485 PCB, Dimension One, D1SR, Serial Deluxe, with Phone PlugDimension One Replacement Board The following topside(s) are compatible with the above circuit board: 58-138-1116 Replaces Dimension One Serial Deluxe product w/phone plug Balboa circuit boards are marked with a “Chip Number” that is located on a white label placed on the logic chip near the center of the board. It is imperative that this number is supplied to Horizon Spa & Pool Parts for proper circuit board match. Just because boards may look similar the programming may not allow it to work properly in all applications. Please review our Balboa Chip Cross Reference below.