We here at SZ have used this amazing little gadgets. Works great on removing and installing upgraded valve springs. Truly a godsend product from JWT for anyone that knows on what's involved for removing the springs. This tool allows a single technician to replace valve springs in a safe and professional manner without removing the cylinder heads from the vehicle. By incorporating a modified follower bucket to compress each spring, the retainer locks can be set on top of the follower and moved safely into place with no chance of falling in the engine, leaving both hand free to precisely complete the job. It can also be used with heads off the engine. Worth every penny at $89.95 even if you only use it once! Fits most Nissan VQ, KA, QR, & VK Engines.