Dura-Block - High End Professional Sanding Blocks (Rating: 5)

Sold at automotive stores or Amazon these are a very nice woodworking tool accessory. They come in many shapes, I have 4. I use them with 3M Stikit paper that comes in 2 3/4 in X 45 yard rolls. 1 roll will last forever.
Dura-Block
3M Stikit
It's nice to have a 16" block with a comfortable grip.