The line extends for 2.4km along the crest of the shingle bank and, when constructed, comprised 691 blocks, each of a standard size, trapizoid in section 1.7m high and 1.5m x 1.5m at the base, tapering to 0.9m x 0.9m at the top. The spacing between the blocks is approximately 1.35m and each block is calculated to weight 1.5 tons. The flat tops of several of the blocks feature the inscribed initials of some of the builders - 'Thomas Roberts', 'Betty Price', 'D Pant', 'DW 1940' and 'LW 1940'. The blocks would have been constructed in four stages using large beach stones with an infil of pebbles, faced with concrete. Where the outer layer of concrete has deteriorated, the banding of the phases can be seen. One of the blocks has been moved to provide easier acess to the beach, but otherwise the line runs from SH61101201 in the south out along the spit to terminate at SH61081433. At the southern end of the line, a small number have been deliberately moved and toppled to make an added barrier to the top of the sea defences. Moving northwards, many of the blocks are exposed to their full height. Further northwards still, some have become engulfed by the shingle bank, and have become covered by sand and grass.

Sources include:
Defence of Britain Project (Record Number 3242)
Record derived from Defence of Britain Project (Record Number 12287)
Parry, M, 2013, World War II Defences of the Shores of the Mawddach Estuary, RCAHMW Collections
Redfern, N I, 1998, 20th Century Fortifications in the United Kingdom Vol II, Site Gazetteers Wales, Council for British Archaeology
Ruddy, A J, 203. British Anti-Invasion Defences 1940-1945, pg4-6
Wills, H and Cooper, L, 1985, Pillboxes - A Study of UK Defences

RCAHMW Aerial Photographic Collections:
RAF 106G/UK/1468, Neg Nos: 2202. 6201-2
RAF 540/373, Neg Nos 120-127
RAf 540/394
Ordnance Survey 76-120, Neg Nos 024-027

Maritime Officer, RCAHMW, March 2016.