Ideal for use on installed cylinder heads, especially in vehicles with tight underhood clearances, but can be used for bench work as well Spring loaded jaws easily grip and compress valve springs Legs designed with a built-in offset to compensate for spring wind - keeping tool vertical and stable during use Includes two spring adapters; fits valve spring retainers up to 1-13/16 inch diameter; 1-3/8 to 5-5/8 inch jaw opening; 5-7/8 inch throat clearance International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions.