OATEY 272981 Cherne® 15" T-Handle Gripper® Plug with 3/4" Bypass

Maximum back pressure is 10 psi (0,7 bar), which works out to 23 ft. (10 M) of head. That is the number to check against your test column height before you set it. Go beyond it and the plug can move.

The bypass is a 3/4 in. male connection through the center of the plug. It lets you keep flow moving, drain down a line under test, or attach a gauge or fill hose without pulling the plug. Cherne Gripper plugs come with or without bypass; model 272981 is the bypass version.

It can be left in for long-term applications. The body is heavy-duty aluminum and the seal is a chemical-resistant neoprene O-ring, so it holds up to extended service in a sewer or storm line rather than being pulled the same day.

The Gripper is a mechanical plug: you turn the T-handle to compress a neoprene O-ring against the pipe wall, so there is no air line, no compressor, and no bladder to puncture on rough concrete or clay. It holds 10 psi back pressure and is rated for long-term placement. An inflatable ball flexes to cover a range of diameters instead; the Gripper is sized to one nominal pipe size, here 15 in. (380 mm).