These kettlebells have a steel core,and they are covered by polyurethane material.This material promotes performance advantages in competition by preventing more peeling,scratches, and damage than traditional paint.Polyurethane material composes of a strong gloss texture and is extremely impact resistant.Our polyurethane kettlebell fulfills the standard competition requirements.Sizes of the kettlebell remain the same throughout different weight levels.Lifting technique for each weight level can remain the same as a result of the standard handle and kettlebell size.We designed this kettlebell to have a hard chrome surface which resist peeling and rust more than all others.