1.Grab Type Selection Reference：Grab Bucket is more used for disperses the shape material handling, in the selection of material should be refer to physical performance, the accumulation concentration, block size, particle shape, the internal friction degree of materials and the loose degree, etc. According to the different packing density and block size, grab bucket is divided into light, medium, heavy and super- heavy.Grab materials block degrees is more than 60 mm or more solid materials, the capture cutting edge should be made tooth.Grab type selection table:Material Packing density(specific gravity) ＜1.2 t/m3 1.25-2.0t/m3 2.0-2.8t/m3 ＞2.8 t/m3MatchGrab type Lighttype Middletype Heavytype OverHeavy type2.The rate of opening and closing rope pulleypowerful matchingTherate of the opening and closing rope of pulley and the closing force of thegrab is directly proportional to the relationship. The smaller rate, the fasterclosed speed, but it can cause grasping force insufficient.The bigger rate,the slower closed speed and exacerbate the opening and closing rope wear.Thepulley of the grab mapping table:Grabtype Lighttype Middletype Heavytype OverHeavy typePulleyrate 3-4 4-5 5-6 6-8