... long widely spaced ,chisel-shaped inserts and considerable cone axis offset against center line of bit ensure very high penetration ... rubber o-rin provides adequate sealing for bearing durability .5.size and model we can provide: 60mm,65mm,76mm ... ,120mm,127mm(5”)130.1mm(5 1/8”),133.3mm(5 1/4”),139.7mm(5 1/2”),142.8mm(5 5/8”),149 ... .2mm(5 7/8”)152.4mm ...