Here's the first link I found when I googled it.
http://www.honeybeefabrics.com/store...duct=SuperBobs
Apparently Superior is out of stock on their website.... ???!!?
If you google "Bottom Line SuperBobs donut", you should be able to shop around more.
They have 2 sizes; L is a DSM-sized bobbin and has 118 yards. M is a longarm-sized bobbin and has 215 yards. Unless you do a ton of applique, you'll want the size L.