Mayuri's arm has been modified, allowing him to launch his hand over long distances as though it were a grappling hook. When doing so, his forearm bloodily separates into multiple segments, all connected by a long, thick cable. His hand explodes when damaged, but causes him no pain in doing so. After his arm has been fired, he can jettison the mechanism by squeezing the stub left on his upper arm. While this temporarily leaves Mayuri without an arm, he can simply regenerate it by injecting himself with Hojiku-Zai.
↑Bleach Official Character Book 3 UNMASKED; Page 155