... 2.Low noise3.high speed 4. high precision5. long useful life.2.Production bearing types: 30*47*1830BD21983A69330BD4718 30*47 ... production completely in accordance with GB/T283-2006 cylindrical roller bearings technical standard production. 2): Our factory have already passed ... components, pumps, machinery.we are the original Manufacturer the bearings, with no Middleman involved ,so we can provide you ...