Economy Blue Handheld Vacuum Pump with gauge and 19.5" tube. Experiment with air pressure and atmosphere, vacuum filtering and checks for leaks. This pump features a gauge in inches, Hg. Displaces 725 ml of air. Pump rate of 15 ml Blue tubing is 19.5" with 6mm inner diameter. Pump goes up to 29mmHg. Not for heavy continuous pumping. Rubber O ring will roll in cylinder at 20 HG after approx. 10 pumps - can be disassembled to be serviced / oil when needed. NOT For automotive use.