Restore like-new performance to your fixture with this thermostatic cartridge — Sigma 18.30.147 Thermostatic Cartridge 3/4". For Sigma. Designed as an OEM-style replacement for Sigma, it's precision-engineered for an exact fit and long service life, installing cleanly with no modifications to bring back smooth, reliable operation.
18.30.147 Thermostatic Cartridge 3/4" GENERIC 
The Plumbing Part Doctor specializes in hard-to-find replacement parts for luxury showers, tubs and faucets — helping you repair the fixture you have instead of replacing the whole system. All parts ship from our U.S. warehouse with flat-rate standard and overnight options. Need help confirming compatibility? Our parts specialists are just a call away.