Metric Single End Open Insulated Wrenches for Working at Height Secure Tools offer a wide selection of metric single end open insulated wrenches for working at height. Available in a range of metric measurement sizes, our single open-ended wrenches are ideal to use in a variety of construction industry tasks Comprised of top-quality, hard-wearing materials, our collection of single end open insulated wrenches are long-lasting and very effective in protecting against electric shock and arcing up to 10,000 volts. Additionally, each metric single end open insulated wrench comes with a useful open ring attachment point, letting you tether the item to your harness to prevent tool droppages when working from height.