Explosion-proof combination wrenches wrench is used, in the machine shop process is completed, we will conduct a series of tests. Appearance quality: Wrench surface should not have cracks, burrs and obvious cracks, cuts, scale and other defects, the handle should be straight. Dimensional inspection: wrench dimensions shall comply with the relevant provisions of GB4388 and GB4389 two standards. Tolerance spanner wrench holes open and shall comply with GB4390 standards. Specifications: 6 sets, 9 sets, 11 sets, 13 sets. With reasonable design, stable structure, high material density, strong anti-strike capability, not off, constantly, bend, high dimensional accuracy, durability and other characteristics. Tools for explosive gas areas, made of aluminum bronze, beryllium copper alloys. Widely used in petroleum, chemical, and other potential fire and explosion hazards in the environment, but also good mechanical machinery essential for the maintenance tools. Both qualities can play a proof function, and where beryllium alloy products can also play a shielded function. Currently in the domestic production, sales, distribution of explosion-proof tools to distinguish the material can be divided into two categories: 1. aluminum-copper alloy (commonly known as aluminum bronze) proof tools, specific material is a high purity copper matrix by adding an appropriate amount of aluminum, nickel, manganese, iron and other metals, copper-based alloy composition. 2. beryllium copper alloy (commonly known as beryllium bronze) proof tools, specific material is a high purity copper matrix by adding an appropriate amount of beryllium, nickel and other metals, copper-based alloy composition. Both thermal conductivity, electrical conductivity materials are very good