These vinyl dumbbells have been ideally designed without any welds, weak spots or seams, they come with a 2mm vinyl coating that ensures a soft and comfortable grip preventing the build up of callus on your palms. They have been designed with refined metal orbs in the casting process and the iron core comes with significantly fewer air bubbles and sand holes. What truly makes our dumbbells so special is that ours are significantly thicker the standard ones on the market making them of a much higher quality.