Holmbury Hydraulic Couplings and Valves - Holmbury Pioneers of the first flat faced couplings in the market, Holmbury are recognized for its high quality, reliable products. Holmbury Group design and manufacture hydraulic couplings and valves to supply the hydraulics industry world wide. Holmbury boasts an extensive range of couplings and valves in a variety of materials to suit a variety of applications and industries.