All ponds are made from 4mm thickness Corten steel for strength, have an overflow pipe (situated under the top edge in one corner), a drain plug (1' BST Thread) that can be used as an inlet/outlet if required. Corten steel ponds are lined with black, non-toxic, rubberised pond-liner paint. The Lacus corten steel ponds are available on backorder if not in stock. They will be at various stages of weathering depending upon the time from manufacture and storage conditions. They are stored outside to allow them to weather as fast and naturally as possible; this could mean that there is *'residue' on the inside of the pond or **'signs of animal life' on the surface -we will clean them the best we can (without removing the already weathered surface). However, there may be marks left that will dispear and weather-over in time with the natural weathering of the pond.