3M 391 1254 Ear Plug Dispenser Refill, Bullet, 33 dB NRR, Uncorded, Roll Down, Disposable, 500 Pairs G4149713 55 cfm @ 30 psi 55 cfm @ 30 psi Maximum Intermittent Pressure 60 psi Outlet Connection Type NPT Inlet Connection Type NPT Package Quantity 1 ) 132 Features Base of 50 x 60 Millimeters and a Height of 9 1 4 in Step Type V Step Screw Type Metal Knob Fine Adjustment Position Fine Adjust Top (FAT) Base Type Magnetic Holding Power 600 N Compatible Indicator Mounts 6 mm Magnet Type On Off Knob Maximum Reach 232 mm Arm Type Rigid Includes Snug Yes Centering Arm Shank Type Straight Overall Depth 10 in Insertion Method Roll Down