Tempo
The Tempo is an unusual razor. Its a Single Edge but takes a full Double Edge Blade. In order to insert the blade the head is tilted 90°, which then frees the top cap allowing you to open it and place a blade on the base plate. Reversing the process closes it up. Besides the centre notch, here are also two notches on each side that lock the head in a tilted position allowing it to be used in three different positions.
They were made of brass and some were plated, however this one was not.
Looking at the flat plate at the back of the razor it has "TEMPO", "D.R.P. ang" and "GERMANY" engraved on it.
The "D.R.P. ang" apparently means German Reich Patent Pending. A patent search has not brought anything up.
The word Reich probably ages it somewhere between 1933 and 1945. (However I am happy to be corrected)
How does it shave?
Its mild - very mild.