Made of high quality carbon steel, high hardness and strength, also very durable. Self-adjusting wrench: automatic locking with adjustable jaw capacity, easy to use in one hand, simple and practical. Two sizes of wrenches in one set: 10.4 inch wrench has jaw capacity of 14-30 mm, 15 inch, spanner has a jaw capacity of 30-60 mm, work well with various nuts such as prism, square, diamond nut, etc., 14-60 mm specifications. to your different needs. This adjustable wrench also has hardened serrated teeth on its jaws. The hard teeth can bite into the softer metal of the round tube and provide the necessary grip to turn a tube. The ergonomic TPR handle secures your grip at the strongest point and keeps the user's wrist in a normal position to reduce stress and improve productivity at work. Tapered crowbar design at the end of the handle makes the wrench more useful.