Cherne® Gripper Mechanical Plug by Oatey
Designed to test drain, vent and waste systems to 17 PSI backpressure
Extra large zinc wing nut for ease of tightening. No wrench required
Natural rubber O-ring for excellent expansion and memory
ABS glass-reinforced plates for added strength
Made of rust and corrosion resistant materials
Available in sizes:  1-1/2", 2", 3", and 4"