The Lost Driver (ロストドライバー Rosuto Doraibā) is the transformation belt, which is shown used by Kamen Riders Skull, Eternal, and Joker. It is a Second Generation Memory Driver and its design is the same as the Double Driver except it has only one Memory Slot to insert a Gaia Memory. The Lost Driver was given to Sokichi by Shroud to aid him in his battle against Museum. She may have stolen it from Museum, as hinted by Saeko's reaction to Sokichi using it. After the death of Kamen Rider Skull, Sokichi, as a spirit gave his Lost Driver to Shotaro in order to become Kamen Rider Joker to rescue Philip from NEVER though the belt was lost during the fight.