The explosion -proof hand stubbu should choose the appropriate specifications. We know that the explosion -proof hand pulling the gourd is 30 tons or even larger specifications from 0.5 tons. The selection of specifications cannot be blindly selected for a large tonnage, or you must choose the appropriate tonnage. The larger the tonnage, the larger the self -weight, and the larger the volume. You cannot choose a small tonnage with a small volume because of the lightness. For example, if you need to load 1.1 tons, can you choose 1 ton? The answer is not possible. The 1 ton is a large specification, that is, 2 tons. The weight of the thing that needs to be loaded is within the standard weight of the gourd.