Features 【Fitment】Universal tester use on 0-300LB, 5LB Increments Valve Springs. 【Quality Tools】Precision tool for the professional & normal Users. valve spring testers allow you to evaluate your valve springs with a high degree of accuracy. 【Function】Valve spring pressure tester is an invaluable tool for you to restore old engines, build new ones, or tear them down between rounds. 【Mini Version】These mini testers can be used in vise jaws or an arbor press. Portable design for garage or at the track. .