Undress coat of a Commodore, 2nd Class, this double-breasted undress coat of superfine blue wool belonged to Commodore H. Caldwell. It has a rolled collar which is shaped with rows of running stitch. There are two rows of eight gilt brass domed buttons. The buttons feature a rope twist edge with a raised inner border and a crown and anchor on a lined ground.

There are three gilt brass buttons, a remnant of the Georgian naval uniform, on the cuff with the distinction lace above them. The distinction lace on the cuff indicates the rank of the wearer: one wide band of gold lace above one narrow band (it should be noted that the narrow band is of an older pattern of gold lace). The top row of lace features the distinctive 'curl' introduced into Royal Naval uniform in 1856.

The 'single stripe of broad lace (1 ¾ inch) on the cuff' for a Commodore 2nd Class makes its first appearance in the 1863 Regulations. However, these did not mention whether or not the curl should be included. This was rectified the following year.

The sleeves are gathered and padded at the shoulder and to the back of the coat are the three-point pockets with blue twist embroidered button holes and three corresponding gilt brass buttons below them. Again, this is a hold-over from Georgian naval uniform. There are two hip buttons and two buttons on each side at mid point and at the bottom of the sword pleats which, beginning in the early 19th century, provide access to the pockets.

The coat is lined with superfine blue wool with the exception of the small of the back and underarms which are line with black silk twill.