A very interesting Combination. The end slides out to reverse from one to the other but there is also a slit in the barrel and a small pip on the pen/pencil piece to match the slot so that it can only go in/out in one way. The barrel has the word “Registered” and the date “11 DEC 1847”. The 11 and 1847 are quite clear but the DEC is rubbed. P&A filed a design registration for a compound pen/pencil-case on that date; registration # 1291.