The T&S Brass 67L Stem Cold TSB, available at PartsFe copyright, is a replacement stem for T&S Brass faucets, specifically designed for cold water lines. This stem controls water flow, and replacing a worn one prevents leaks and restores smooth operation. The "TSB" likely designates a specific T&S Brass series or feature. https://partsfe.ca/67l-ts-brass-stem-cold-tsb