These basic nylon plastic casters measure 1in. in diameter and offer a simple solution for robotics mobility. These caster balls provide smooth, effortless movement. Note: These are the same casters used with the XRP kits Beta & DIYIncludes: * 2x Nylon Ball Caster https://elecena.pl/product/25290190/caster-2-pack 2024-02-08 https://elecena.pl/product/25290190/caster-2-pack 2025-04-13