Henan Shenlong Petroleum Drilling Tools Co., Ltd is one of TOP 5 manufacturers producing drill collar, heavy weight drill pipe. We are Sino-USA Joint venture. USA partner is from MIT, they are experts of metal materials. We have strong fund and technology background. Our registered investment is RMB10, 000, 000, Our first investment reach RMB50, 000, 000. Shenlong&＃039;s products have been widely used among famous china oilfields, for example, zhongyuan oilfield, changqing oilfield, shengli oilfield, xinjiang oilfield, daqing oilfield etc. Our products enjoy excellent reputation with good quality, competitive price, prompt delivery time. Shenlong?s products have been proved by many oilfields: there is no thread gluing and no fracture after they drill 600 hours. our products can last much longer time than any other competitors&＃039;. Drill collars we provide are from 4 3/4" to 11", Heavy weight drill pipes are from 3 1/2" to 5 1/2" We provide free thread protector for both box and pin.