The jackets constitute the foundation that carry the two offshore high voltage stations in the heart of the Gemini operation in the North Sea. Each jacket consists of four legs (tubular profiles diameter 1.4 metres, length 58 metres) with intervening links and brancings, four mudmats at the ends of the legs for stability during installation and four pile sleeves containing the piles. The jacket also contains two boat landings (for access by crew boats) and the J-tubes to house the cables that deliver the power from the turbines and convey the electricity to the mainland.