The SP Tools Valve Spring Lock Down Tool, No. 91400B-LDT, has been developed as an upgraded accessory for SP Tool's popular Updated Universal OHC Valve Spring Compressor (No. 91400B), which bolts to the cylinder head and simplifies the process of removing and re-installing valve springs.In operation, the Valve Spring Lock Down Tool keeps the valve spring and retainer compressed for hands-free removal and installation of the valve keepers. This tool is very versatile and can be fine-tuned and locked down to provide a hassle-free valve spring service.