A workhorse bobbin that allows for excellent tension control (by bending arms), silky thread-feed and smooth steel tube (minimize thread-breakage). Make sure you have a few of these with your favorite thread colors handy.
Legit best bobbin around. The ball ends hold tight and make the spool unravel smoothly unlike other "pinch" style bobbins. The grip is comfortable helps your hand not to cramp as much on those long seshes.