The Pentek US-1500 water filter system replaces the Culligan SY-2650 system. The parts and replacement filters are the same. The Pentek US-1500 is an under sink water filtration system that uses any of the following water filter cartridge sets: D-250, D-250A, P-250, P-250A. The US-1500 features an electric monitor that the US-1000 does not have. The monitor electronically tracks your water usage and reminds you when it is time to change your filters. The Pentek US-1500 is NSF certified to reduce 43 different contaminants including VOCs, lead, cysts, mercury, asbestos and chlorine taste & odor. The US-1500 systems comes complete with cartridges, a long reach faucet, filters, electronic monitor with battery, wrench, o-rings, instructions, 1/4" tubing, and installation hardware including mounting screws, T-adapter, and quick-connect elbows.