William E. Haley

Diamondback Holdings LLC provides oilfield services.

Serva Group LLC manufactures, distributes and installs gas and oilfield equipment for the energy market. Its product range includes cementing, stimulation, coiled tubing, pumps, and controls. The firm serves to the fracturing, nitrogen, cementing, blending, and drilling and down-hole tubular industries. The company was founded by Pete Seitz on February 11, 2009 and is headquartered in Tulsa, OK.

Mammoth Energy Partners GP LLC provides oil and natural gas exploration services. Its offer services to independent oil and natural gas producers and landbased drilling contractors in North America. The company is headquartered in Oklahoma City, OK.

SJS Ltd. is a joint venture between Sinopec Petroleum Machinery Co., Ltd. and the US-based SEW Group. The private company is located in Jingzhou, China, a historic and cultural city on the banks of the Yangtze River. SJS is a renowned manufacturer of petroleum drilling and production equipment, known for its top-notch technology, products, and service quality. The Chinese company offers a range of products, including intelligent control systems, pump products, power components, and equipment for increasing production. SJS has developed and manufactured thousands of plunger pumps and centrifugal pump products for global onshore and offshore oil fields, and provides comprehensive parts and fast response services to create more value for customers worldwide.

EnTrans International LLC engages in the manufacture of tank trailers, oilfield equipment, and related components. Its brands include Heil Trailer, Heil Trailer Export and International, Polar Tank Trailers, Polar Service Centers Kalyn Siebert, and SERVA. The firm offers aluminum and stainless products for the liquid, dry bulk, oilfield, and construction industries. The company was founded in 2014 and is headquartered in Athens, TN.