Ballpoints Pens - The Twist Mechanism
All Ballpoints pens with a twist mechanism take the Cross refilI. This is easily obtainable at most high street stationary retail outlets and are available in a range of colours.
To change the refill simply pull the top of the pen off by hand do not use any tool except in some cases maybe a cloth, if it is tight. Unscrew the refill and remove then screw in the new one being careful not to damage the thread as this is only plastic. Push the top back on and re-allign the pen to your satisfaction. Be careful not to drop the ring during this operation.