Rebellion Alpha Trion and Optimus hands

Cybertronians have hands that help them, similar to what humans have. Despite not having skin like humans, Cybertronians have mechanical hands and mechanical fingers. Not all Cybertronians have five fingers, like humans do, and the way in which hands are structured differ on Cybertron. It is possible for a Cybertronian to lose a hand. Ultra Magnus' right hand was brutally damaged by Predaking who stepped on his hand and crushed it into pieces. Ratchet was able to replace Ultra Magnus' hand with a mechanical claw. Ultra Magnus would eventually regain a new hand as his original sometime after Cybertron was restored.