Aha! There's the secret. You bought it from a Cat dealer. Cat markets Trimble products under the Cat brand also. Here's the rub - If you walk in off the street and say "I have a Dual Dozer with twin Trimble GCR-2SM receivers and a wired remote control with a Rexroth valve block. What laser control system will work with that valve block? A CB30 with dual LR50 receivers? Oh, and I'm just a one-man show". Their eyes will just gloss over and you get the thousand-mile stare. They will tell you that your antiquated laser system is irreparable, nobody will touch it for any price. You'd be best off buying a whole new GPS system. They won't even mention a new laser system. The GCR-2SM system is pretty quick too. Quick enough for me at least. Hahaha. I bought my system used and set it up myself on both machines. It's not rocket science, but the manual came in handy.