This is a newer model of Dr. Pen. It is simple and easy to use. The pen is not as bulky, so it's easier to hold when used for the whole face. This electric pen feels less painful than manual roller and covers the small areas much easier than manual rollers. The kit came with 20 replacement cartridges. Since micro-needling should only be done every few weeks, these replacement cartridges will last a while. Other than the well made machine, another good thing of Dr. Pen is the cartridges are readily available due to its popularity. Despite this is a simpler version, it has everything one needs for micro-needling. So the kit is a great value. And a great durable device for any home or salon users.