Get to working out, saving time, and building muscle! P.S. To lose weight, you don't need to do cardio!Now you could focus on muscle building with your new dumbbells.You could do squats, dead lifts, curls, floor presses, shoulder presses, triceps extension, etc and each time you could get a really great workout in just 15 minutes (and that's all you need!). There's nothing better than being able to workout in the comfort of your own home. No need to get dressed, no need to waste time (or money) driving to the gymThe collars do hold the weights on quite sturdy, even when doing something like triceps extensions (with the dumbbell totally vertical and the weights aimed at the floor).This high quality dumbbell set is made of concrete weight plates and chrome finish bar. It comes with different sizes weight plates for you to adjust to your desirable dumbbell weight. This weight plate set features with 2 pairs of spinlock collars and non-slip grip to provide you a safe and secure exercise experience. It is great for both upper and lower body workouts, which helps tone and sculpt your arms, shoulders, back and also strengthen your muscles. With this dumbbell set, you can exercise at home, in the office or any place at any time.Features:Adjustable weight for diverse muscle training;Foam covered connecting rod to reduce neck's compression and relieve fatigue;Non-slip design with rubber coated handle for firm grip;Quick conversion between dumbbell and barbell, with the connecting rod;Easy to dissemble and assemble;Features with comfy PVC grip to prevent slipping and pertect your hands effectly when exercising;Specifications:Material: plastic, cement, electroplated iron;Color: blackPackage content; please refer to the picture for detailsNote: Weight = the sum of dumbbell weight + dumbbell bar + connecting rod.