16″ Toilet Supply Connector — 3/8″ Comp × 7/8″ Ballcock, Braided Stainless

A toilet is one flush away from a slow drip becoming a floor repair, and the supply line is the part that decides which. This connector bridges a 3/8″ compression shut-off to the 7/8″ ballcock inlet under the tank across a 16-inch flexible run — the extra length that reaches when the stop sits low or off to the side. Inside is a PVC core; outside, a 304 stainless braid that contains the hose if the core ever swells, so it weeps instead of bursting. The 7/8″ outlet nut is glass-reinforced nylon that threads onto the porcelain-tank inlet by hand and won't crack the fitting or corrode in a humid bathroom, while the 3/8″ compression end snugs onto the stop with a nut and ferrule. No tape, no tools beyond a quarter-turn snug. It's the quiet part of a toilet install you want to forget about for a decade.