The ScanNCut sharpie holder is made by a UK company called 3DFunPrintz – it uses Sharpie Fine Point markers which do not fit in the Brother universal pen holder.
You can shop for it here: https://3d-fun-printz.mybigcommerce.com/
Sharpie fine points are easily found at lots of retailers – for best current prices, shop around.
I absolutely LOVE this pen holder – it is made from recyclable plastic (PLA) which originates from cornstarch, which is brilliant.
Fine point Sharpies literally come in a rainbow of colours and are a permanent, alcohol based marker.
As you can see in my video below , it is extremely simple and hassle free to use – insert the sharpie, screw the cap on and the pen automatically has the right tension for creating your designs.
I do however recommend increasing your line spacing – see the video for how the line spacing function works and how to adjust it to best suit the pen in your holder.