Item Specifications BrandSanyo Denki, San Ace 40, 9CR counter rotating Model9CR0412S543 QuantityLot of 12 fans Frame Size40 x 40 x 56 mm, 12V DC DesignTwo impellers stacked in one housing, turning in opposite directions. Built for 1U servers and switches, where a single rotor cannot move air against high back pressure. WiringTwo separate 3 pin connectors, one per rotor. Both must be connected for the fan to run as designed. PerformanceNot published for the -543 variant. The sibling 9CR0412S501 is rated 24.7 CFM, 450 Pa and 57.5 dBA – a family reference, not a specification for this part. ConditionNew – Open box, never installed TestingNever powered up. No running test is claimed for any unit in this lot. Included12 fans only. No mounting screws, guards or adapters. Shipping & Returns ShippingFree Shipping Return Policy30 Days Free Return