Use only the Original Manufactures refills. They are completely different pens. The super smooth high impact resin allows your Sensa Stylus to glide over any computer pad with style and ease. In the retracted position your stylus point is protected and your clothing is protected. When you replace the refill it does not come with a new spring.
Springs are available upon request.
Remember that the Pressurized refills have PR on them, while the Rollerball has X-400 Do not tap, use excessive force or drop your pen on its tip. When dropped the nib is pushed in and you loose the nitrogen pressure causing the refill to become erratic. To replace the refill , hold the Grip in one hand and the barrel in the other.