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The ZX 1000 electric 1_______ has two speeds: the fast speed is 3,000 rpm and the slower speed is 1,000 rpm. Adjust the speed according to the 2_______ of material and the size of the hole. For example, use the faster speed for a soft material such as 3_______ to drill holes smaller than 10 millimetres (10 mm) in diameter but choose the slower speed for holes between 10 and 25 mm. However, for steel, a 4_______ material, use the faster speed for holes smaller than 6.5 mm and choose the slower speed to drill holes between 6.5 and 10 mm.