Restore like-new performance to your fixture with this cartridge — Sigma 18.30.081 Thermo Cartridge. 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.
SIGMA THERMOSTATIC REPLACEMENT CARTRIDGE.
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.