A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the aft crew accommodation space between 103 and 117 stations on the main flat looking to port, aft and up on the port side at 109 station showing a slop drain pressure gauge above two BU6 Short boxes and oxygen candle stowage against the port side of the boat with a ventilation fan unit below them. A control box for the submerged signal ejector is under a plaque headed 'Modification Record Equipment S.S.E. Mk. 2'. A vertical format negative.