This O-ring is a replacement for the O-ring Manifold Fittings. The O-ring should be removed, cleaned and inspected periodically. If dry, it should be lubed with O-ring lubricant (HLUBE). If damaged, it should be replaced. O-ring lubricant will prolong the lifespan of O-rings and help create a watertight seal. TMOR 1" O-ring FITS: All 1" Manifold Fittings. TM112OR 1 1/2" O-ring Fits: All 1 1/2" Manifold Fittings.