- A A --- Products --- Oil Seals O-Rings Bearings Adhesives & Sealants Belts and Pulleys Chains and Sprockets Welcome Welcome to Blue Diamond on-line - the latest service from a well established company looking to maintain our envied high standards of customer support and product availability. Specialists in the design and supply of rotary shaft seals, O rings, and sealing related products the ...www.blue-diamond.co.uk