Vanguard Competition Kettlebells are constructed of high quality steel. There is no filler used to make the weight of Vanguard Competition Kettlebells. The Vanguard Competition Kettlebells are constructed with solid steel handles. No toxic heavy metals are used within Vanguard Competition Kettlebells to create heavier competition kettlebells. The surface of the Vanguard Competition Kettlebells is blasted with micro glass beads to create a uniform texture that aids in gripping the handle of the Kettlebell. Vanguard Competition Kettlebells easily accept chalk or can be used without chalk. Steel is far more durable than iron and offers a more balanced kettlebell.