Knuckle's Maximum Break (ナックルの極限ブレイク, Nakkuru no Makishimamu Bureiku) is the circumstance in which the First Generation Vongola Guardian of the Sun Ring, Knuckle, gave himself a three minutes time limit and saved the Vongola by boxing. Through future Vongola technology, the 10th Generation Sun Guardian, Ryohei Sasagawa, can use Cambio Forma to re-enact this circumstance. During Cambio Forma, Ryohei's body is shot by the Sun Enhancement Shot. His Vongola Box Weapon, Kangaryuu V.V.B., transforms into a set of gloves and a helmet.