9v power supply = CASIO CTK 591 574 573 571 540 keyboard

Multitester tested for voltage. This is a voltage EQUIVALENT wall mount version for theCASIO voltage regulator, power supply, powersupply, inverter, adaptor to the Casio MT-35, MT-36, MT-240 MT-640, MT-820. Please check your device compatibility before looking. AC input 120V and DC output:9volts DC 0.850A (9VDC 850mA). Amperage can be higher, but never lower. Round barrel connector with aNEGATIVE center. Shape, size or color may differ from product photo.Special heavy wrapping is provided to protect the prongs. S&H in the contiguous USA is $7.(insured shipping).Please see other interesting products by JGritUSPS DELIVERY TIME: As stated in the item listing, seller will drop-off your item to the USPS within 4 days of receiving cleared payment. How long it takes to deliver to your door is strictlywithinUSPS control and not within the control of seller. Please leave 5 stars for seller 4 day drop-off time. Thankyou.