Tuf-Tite Plugs & Seals- Snap-in pipe seals - they're patented. Simply insert your PVC pipe and push it through the flexible, polyethylene Tuf-Tite seal. Pipes fit watertight. Installation couldn't be easier.- They're permanent - unlike cement-based pipe grout, Tuf-Tite seals will not crack or corrode in septic conditions. - S-35 Pipe Seal for sewer and drain, SDR35, thin wall, ASTM 3034, 1500 lb. crush.- S-40 Pipe Seal for Schedule 40, 4" corrugated.- P-10 Plug, for unused holes.Tuf-Tite Speed Levelers™ - Control the flow of effluent from the Distribution Box. Simply insert a Speed Leveler into each outlet pipe. Rotate each Speed Leveler so the flow is distributed as desired.- Available in 3" or 4" PVC pipe.