Tesco makes tools for those who work alfresco. The company makes drilling equipment for oil and gas producers worldwide and is organized around four business lines: top drives, tubular services, casing drilling, and research and engineering. Tesco maintains a rental fleet of portable units, or top drives. Its Tubular Services unit offers proprietary offerings and conventional casing and tubing running services. Tesco's casing drilling technology allows drilling of wells without the use of drill pipe. The company's blow-out preventers and active control units are used for snubbing, air drilling, and underbalanced drilling. Tesco also offers complete drilling rigs, drilling machinery, and related equipment.