This cable allows you to connect the Drake L4 ,L4B or any other amplifier to the Relay connection on the Drake AC4 Power supply. There NOT OEM cables but work very well. The OEM connectors originally supplied by Drake over the years either broke or were lost. I have been restoring Drake equipment for awhile and have sold many of these cables. There 48 inches long with a 2 pin connector on one end and an RCA on the other. There 100 percent quaranteed satisfaction or your money cheerfully refunded. Buyer to pay $4.00 shipping CONUS .International buyers pay exact costs via USPS airmail.