These are the adjustable dumbbells that fix 4/5 problems every adjustable dumbbell has. 1. Too light: these go from 10-120lb 2. Slow to change: quick magnetic adjustments 3. Feels like a toy: these are all metal construction 4. Oversized: plate steel make these very compact 5. Don’t feel like a fixed db: theyre close, but still have a cage They’re called the REPxPepin Fast Series.