Eclat 12 mm Thru x 142 mm 40 Hole Coaster Brake Bicycle Rear Hubs
About Eclat - "Simplicity is the hardest design principle to follow; It's at the heart of our approach to eclat."
This is hub spacing and is the width of the hub. It must match your frame specifications.
The hub drilling is the number of spoke holes. It must match your rim spoke count.
This should correspond to the type of brakes you have on the bike.