The shop has both Magna Glide Delight bobbin in 40 wt Glide Thread and Magna Glide Classic bobbins in 60 wt thread available.
The M size are larger but in the Delight Jars there is a total of 1210m of thread on 10 bobbins. The L size Jar has 20 bobbins with a total of 1320m. You can use L size in your M bobbin case!
The Magna Glide Classics are available in Boxes of 72 for the colours or 100 for the Black and White.
I also break down the boxes into Budget Packs of 24 bobbins in the non neutral colours. As the Classics are a 60wt thread an M size Budget pack contains 4872m of thread. The L size Budget pack contains 2880 metres of thread.
Just a little play with numbers after restocking the shop this morning!