The FlexPower C4, C8 lock controller modules add either 4 or 8 lock control outputs to a FlexPower power supply and are typically supplied as part of a system or purchased as an expansion piece to an ...The FlexPower C4, C8 lock controller modules add either 4 or 8 lock control outputs to a FlexPower power supply and are typically supplied as part of a system or purchased as an expansion piece to an existing system.