The life maxx cast iron kettlebells with rubber foot are the most traditional kettlebells in our product range and are suitable for intensive commercial use like the russian kettlebell system it is based on this kettlebells diameter increases with its weight our cast iron kettlebell features a rubber foot this is designed to protect floors and racks the lmx90 cast iron kettlebells with rubber foot feature a smooth durable coating that makes them comfortable to use the life maxx cast