Weber # 99241-2-1/2" Stem Style Locking Swivel Caster with Insert. Weber part # 99241 - 2-1/2" Stem Style Locking Swivel Caster with Insert. This replacement caster is sold individually and fits several Weber Genesis and Spirit series grills. This caster is used commonly with Weber 8" Wheels Part # 99252 Please visit Weber's website to ensure you order the correct parts for your specific grill. It is best to look up by serial #. The following link will also help you find the alpha numeric number. http://help.weber.com/schematics/#serial-number