Cross Switch it 0.7 - Pencil Ballpoint Convertor -Convertitore Sfera Portamine

The Cross Switch-it pencil convertor is a pencil lead cartridge which simply substitutes a fully function pencil mechanism for an existing ballpoint refill in a Cross ballpoint pen.
The mechanism slips in and screws in place and, once the push-fit cap is replaced, using the pen's twist mechanism, the lead cartridge extends and a further twist then extends the 0.7mm lead. 
A reverse twist retracts the cartridge to protect any extended lead. 
The Cross Switch-it also comes with an eraser in the end which is accessed by removing the cap.