An organized system for storing wrenches - standard or metric. Patented gripping system holds your wrenches firmly. Shows at a glance when a wrench is missing. Offers instant selection of the right size wrench. Made of flexible and durable Polypropylene Plastic Includes Peel off numbers for SAE and Metric. Label tray to fit your needs. Numbers range from 6mm to 20mm or 1/8" to 1" SAE.