I find that the collars don't fit every type of pen, and there are videos on youtube that a person should watch just so they know how to use this adapter. But it works and is very handy to have. The price here at scrapbook.com is the best, and I received mine in 2 days! So the rating is reflective of the actual pen holder, not scrapbook.com They get 10 stars!
This is a great little accessory. I used it to make return address labels by "writing" the address, then cutting out the label. The reason for 4 stars is because none of the adapters seem to work with a basic sized ball point pen, only larger pens and markers.