Designed for use on the 10mm battery terminal bolts found on many import and domestic vehicles 10mm, 12 pt. box-end ratcheting wrench Slim design and short, 5-1/2 inch long handle allow use in the tight underhood confines of today's modern vehicles Handle and leading edge of tool are both insulated to help protect against unintended metal to metal contact that causes the sparks to start flying Convenient thumb switch changes ratchet direction