Cut cylinder head assembly and disassembly time in half with the Proform pneumatic valve spring compressor. Builds 350 lbs. of force with 125 psi, and will operate on a minimum of 100 psi. The compressor arm slides for adjustment, employing a locking pin for rapid, easy installation. Works on most cylinder heads. Product Features:Adjustable ArmCan Create Up to 350 lbs. of Pressure with 125 psiDesigned for Use While Head Is Off Engine BlockMade from Quality Steel