Ring dial for latitude 51° North. The ring has a fixed suspension piece and a large suspension ring. The outer face displays a date scale, stamped with the initial letters of each month. It appears to be set with equinoxes at approximately 10 March and 10 September. On the inner face is a stamped hour scale numbered 4-12, 1-8. There is a sliding central collar with a pinhole sight set into it, which is adjusted by a buckle-type attachment on the collar.

The quality of engraving on this instrument is low, suggesting that it was most likely to have been made by an amateur.

For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.