One form comes in a puck and is like a long string of cotton. It's a very stiff cotton with quite thick stringy strands which takes quite a bit of prep work to build nice wicks with, (I've only used this version personally and wouldn't rate it as one of the better cottons I've used).
The other form comes in a packet. It's more like the centre of Muji cotton, much easier to work with and prep for wicks.
Don't know if you knew there were the 2 types?? Which one are you specifically looking for bud ???
Been looking at the one in a roll i have only every used muji type cotton so looking at trying something different doesn't seem to be very popular in the UK towards cotton bacon tho