A small slate-roofed building containing a two-seater tiolet perched over the sea. Such toilets were features of both Nicholas Treweek's shipyards - the other, near the dry dock, was possibly the small square building shown at SH45099348 on historic mapping. This example was preserved and restored by Anglesey Council in the 1980s.

Sources include:
NAW aerial photography 2006-9
OS 1st edition 25in mapping

Maritime Officer, RCAHMW, August 2012.