H.10D is a slender handpiece with rotating lever action that releases and closes the collet for quick and easy changes and includes a duplex spring for added flexibility. Use with standard key tip shaft ONLY. H.10D is a slender handpiece with rotating lever action that releases and closes the collet for quick and easy changes and includes a duplex spring for added flexibility. It is one of the few handpieces that requires lubrication as does the duplex spring component. Be sure to read/download the Handpiece Instructions, available under the downloads tab, for proper use and lubrication. For use ONLY with 2.35mm (3/32?) burs. Duplex springs are subject to breakage and are NOT covered by warranty. They are made of special steel, double wound tubular construction with a protective flexible spring cover. Replacement springs (HP76) are available and can be installed by the user. We recommend that only experienced users of flex shaft tools consider purchasing this style handpiece. For most users, the “straight” handpiece (H.10) is the preferable solution. 10-3/4? long, 21/32? dia., wt: 5.95 oz., ship wt: 7.4 oz.