Mr. Crawford's original flareless tube coupling also had certain disadvantages. It did not have four sealing points and once installed it was not easy to remove when bends in the tubing were made close to the nut or if tubing were expanded due to pressure. Also shock and vibration were relayed directly to the coupling seal, a result of the original bushings design.

Cullen B. Crawford, founder of Tylok International, Inc., solved those early problems with the "four-seal" design and has continued to develop and improve this design to the present day. Tylok's patented four-seal design provides more effective sealing area than any other coupling on the market, Tylok's couplings are not affected by shock, vibration, surge and temperature, and feature a fitting nut that can be moved freely around the sharpest tubing bend.

Tylok's couplings may be used over and over again. If installing on a new piece of tubing, only the collets need be replaced. They cannot be incorrectly assembled, cross threaded, misaligned, over-tightened or pulled apart.

The prime requirement for any and all tube couplings is holding power. Tylok's tube couplings provide the ultimate in holding power for extremes of temperature, pressure surges, emergencies, accidents and other service conditions.

Today Tylok International, Inc., is the leader in the industry, offering unique, patented, top-of-the-line couplings - tube, weld, metric, pipe, vacuum and breakaway - and a complete new line of Ball Valves for quick on-off service.