20 kG Adjustable Cast Iron Chrome Dumbbell Set 20KG Dumbbells Barbell Set This Fitness 20kg cast iron dumbbell set offers users a complete solution for increasing upper and lower body strength. Strong and robust, the cast iron weight plates and chrome spinlock bars are incredibly heavy duty. The spin lock collars make it quick and easy to increase or decrease the weight. Strength training is one of the most effective ways to reduce body fat, increase lean muscle mass and burn calories more efficiently, strength training is an important part of any fitness programme. Studies have shown that strength training can also help to increase the endurance of muscles, while also helping to increase bone density, reduce resting blood pressure and improve balance and co-ordination.