This is an excellent example of the famous Watermans Ideal. This is the 52 1/2 in Black Hard Rubber. The pen was made in the USA around 1925 and is in very good condition with a good imprint. The 52 1/2 is the thinner version of the standard 52.
The pen has been fully restored and now works perfectly. It is a lever filler and is fitted with an amazing Fine Full Flex nib.