The EZ Red Hydrometer checks specific gravity of the battery electrolyte solution and is temperature compensating for direct, accurate readings. It is designed so that anyone can see the state of the battery acid and it is great for automotive, marine and commercial batteries. The EZ Red hydrometer is unbreakable, easy to read, economical and used by battery manufacturers worldwide. It has a wide range of 1.100- 1.300 sg. and includes a lifetime warranty.