Low Tension Valve Checking Springs 4758-2 (3-Piece Set) - Precision Valve Spring for Measuring Piston to Valve Clearance & Rocker Arm Ratio - Ideal for Engine Builds, Performance Tuning, and Automotive Repair Shops

I don't know why this is a set of three instead of two or four, but I think that's the only thing I can say that's not entirely positive. These springs are all the same length, have ground ends, and look to be about the right diameter to use in place of many common valve springs. They're certainly longer than a lot of the value springs on engines I've worked on, but that's been mostly smaller car engines, and they're compressible by hand easily, so this just gives more range they will work for.Using my highly-calibrated spring tester (my right hand), I compressed all three to minimum length. They all feel the same weight. Nothing broke, and the returned to the same length as they started. Spring test complete!In all, if you need a test spring or three, these are a good buy. Heck, if you just need a couple good springs for a project, these are a good buy.