... by API-ISO 2.good quality,low price 3.good after-sales service 4.adequate stocks,fast delivery ... , subterranean heat. Hydrology welling drilling and so on.3.It is almost suitable for hard rocks, such as ... 7mm(8 3/8”),215.9mm(8 1/2”),222.2mm8 3/4”) 241.3(9 1/2”),244.4(9 5/ ... 8”),250.8(9 7/8”)269. ... 8(10 5/8”),295.3(11 ...