Imperial Single End Open Insulated Wrenches for Working at Height Secure Tools provide a wide selection of imperial single end open insulated wrenches for working at height. Available in a range of imperial measurement sizes, single end open wrenches can be moved into position from the side of the nut or bolt – great in tight situations. Made of the highest-quality materials, our single end open insulated wrenches are resilient and manufactured to withstand year after year of hard-wearing use– even in tough work environments. Furthermore, the top-quality insulation composition protects against electric shock and arcing up to 10,000 volts. And, each of our imperial single end open insulated wrenches come with a fitted hard-wearing open ring attachment point. This gives you a fixed place to securely tether the tool harness and avert droppages when working from height.