Quickly and accurately test the spring strength of your AEG with the help from this Spring Analyzing Tool from Spring-Tek. Whether you are looking to upgrade your spring and want to compare choices, or are just curious how your current spring is holding up, the Spring Analyzing Tool is a must have for avid airsoft enthusiasts. An electronic gauge is included to accurately display the tension level of your spring. Spring-Tek recommends the user bolts the system in place on a hard non-moving surface for the most accurate readings. Feel confident your AEG is all tuned up and pick yourself up the convenient Spring Analyzing Tool from Spring-Tek.