If you are working on older flathead 6 and similar vintage engines, this is a great tool. I have tried all the other "hacks" to remove and install valve springs and none worked. Plus, there is the safety factor. This tool is a beast and will handle new valve springs on side access valves and springs. My engine is a 1950 Plymouth L Head Flathead six.
Great tool, great value. Fits the valves and lifters of the L134 perfectly. Reaches under the manifolds. Much better than the generic tools from the parts stores.