NTT a handheld drill drum sander. One end attaches to the drill. The other (the red side) is a handle with bearings. Works great for shaping edges etc! : r/Tools
Hand-Held Sanding Drum for Drill Presses and Power Drills | O'SKOOL O'SKOOL
Amazon.com: O'SKOOL Hand-Held Sanding Drum for Drill Presses and Power Drills : Tools & Home Improvement