Cyl-Tec”s aluminum industrial/specialty gas cylinders have a natural shoulder and brushed finish and come standard with parallel threads. Testing and maintenance services for all types of high-pressure cylinders include: U.S. DOT hydrostatic and ultrasonic testing; external shot blasting and spray painting; internal shot blasting and oxygen cleaning; special paint requirements; gas service changes; siphon tube replacement and installation; neck ring replacement and installation; valve replacement; cylinder stenciling and stamping; cylinder cradle repair; cylinder cradle manifold repair.