WW2 Military Abney Level, Artillery Clinometer, Mk 5, 

Marked WRP Mk 5, B6623, with broad-arrow mark.

Original & authentic, not a reproduction. 

Dated 1944, 

Original leather case, marked P.I.C, MK V (5) 1944, broad-arrow 33 

Appears complete and in working order.

Good used condition for age and application, with some slight wear and marks. Plus, the bubble level is cracked and now empty. 

W. R. Prior & Co. Ltd. "Scientific Instrument Makers and Manufacturing Opticians", with a factory in Bishop's Stortford, Herts. and a London office at 28a Devonshire St. Trademark is "WRP" in a diamond.

An Abney level and clinometer is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale. An internal mirror allows the user to see the bubble in the level while sighting a distant target. It can be used as a hand-held instrument or mounted on a Jacob's staff for more precise measurement, and it is small enough to carry in a coat pocket.

Museum example attached below, for reference.

https://collection.maas.museum/object/373221

https://ice-museum-scotland.hw.ac.uk/product/1996-015/