1/2″ White PTFE Thread Seal Tape — 480″ Roll, Standard Density

Tapered pipe threads don't seal on their own — metal against metal leaves a spiral leak path no amount of torque will close. PTFE tape fills it. Wrap the male thread three or four turns in the direction the fitting turns, thread it home, and the tape cold-flows into the root of the thread, filling the void and letting the joint tighten further without galling. It's the same reason it doubles as a lubricant on brass and stainless: threads that would seize dry come apart clean a decade later. This is the standard 0.5 g/cm³ density in a 1/2″ × 480″ roll — the general-purpose white tape for water lines, compression adapters, and threaded brass fittings. It won't dry out, crack, or shrink in the wall, and it leaves nothing to scrape off when a fitting comes apart.