UPGRADED GRIP GROOVE DESIGN: Compatible with dumbbells ranging from 1-1.15 inches in diameter, adjustable kettlebell converter features TBR core with fixed edges; Dumbbell adapter provides secure grip and reduces movement on smaller handles for more comfortable hold CONVERT DUMBBELLS INTO KETTLEBELLS: Kettlebell grip handle for dumbbell transforms dumbbells into kettlebells with a simple 4-step setup, adding versatility to your workout and making kettle grip easy to include kettlebell exercises in your routine