Occasionally you'll successfully pick a lock only to find the lock required you turn it the opposite way. From there you have two choices: Pick the lock again, or use a plug spinner. Having spent sometimes 20-30 minutes picking a particularly difficult lock I think it's fair to say the latter would be preferable.
Plug Spinners do exactly what they say on the tin, they spin the plug. But with such speed and power, the plug can spin over to the other side (from left to right, or right to left, depending on the lock in question) without allowing the pins to spring back into the plug and lock it again. You wind up the spinner, insert it into the lock and press the button. In a ping, the plug swaps sides, and you're free to continue turning the plug and opening the lock.
GOSO Pen Style Plug Spinner