PTF Kettlebells are formed into a strong, balanced, single-piece casting with a flat wobble-free base. A clean, void-free surface and durable powder-coat finish give PTF Kettlebells an unmatched feel. The PTF Kettlebell was designed around these requirements. Premium Material: We started with the highest quality first run iron ore available, not scrap. Void free surface: We use a proprietary casting process so each bell can reach the highest quality and have the cleanest finish possible. This also allows us to have a smooth, comfortable handle. Single Piece Casting: ThePTF Kettlebell is cast in one solid piece, creating a stronger, more reliable handle and a void free surface. does not use plastic caps, plugs, or patches like lower quality products. Wide Flat Machined Base: We chose to machine the base of our kettlebell flat (not leave it as a raw casting) so it sits perfectly on the floor and does not wobble. Finish: The PTF Kettlebell has a matte black powder coat finish that has a great feel and will hold chalk. This feels more natural than a thick epoxy finish. Colors: We color coded the handles. By associating each kettlebell weight increment with a different color handle, it becomes much easier for gym owners and trainers to direct athletes to specific kettlebells on sight alone. Weight increments to choose from-ranging from 4kg to 40kg Weight Tolerance: +/- 3%