Here i show the procedure in replaceing a new diaphragm into a Parker Vacumatic MkI double jeweled fountain pen. The process can be tricky and will need some experiance. If not send your pen to a pen restorer. Please support my work at http://www.paypal.me/grandmiapens Ebay at https://www.ebay.co.uk/usr/welcome2stay Email at grandmiapens@gmail.com