This type is unique to the Essex coastline and is purpose designed to command the flat lying land around the estuaries. It is an elongated octagon in shape having three angled faces of approximately 2m length at either end and 7m long sidewalls allowing the pillbox to straddle what would have been a low sea defence bank. There are five embrasures in each end, three in the angled faces and two in the side walls close to the ends. The entrance was in the middle of one side and was covered by a porch facing inland. Internally there is an anti-ricochet wall that runs down the middle of the chamber which has a T section at the front end of the chamber only. In the years after the war the sea bank has been built up and the pillboxes are now partially buried. The entrances and side embrasures on most have now been covered over.