Standard diving dress helmet. Copper domed bonnet attached to a copper corselet (breastplate) by way of brass neck rings with an interrupted thread and sealed with a leather gasket.
This object is in excellent condition considering its age of approximately 170 years and its heavy usage over that period in diving operations. While it reflects the most basic helmet design, some improvements have been made during its working life. There are only 3 other examples of the Augustus Siebe Diving helmets are known to exist in 2010, and is the second oldest closed diving helmet in known existence.