Your search for "PWR-2900AC" revealed the following:
Arista PWR-2900AC 2900W AC Power Supply for DCS-7508 and DCS-7504 Chassis
SKU: NSH-6281
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 98.99
• Only 2 remaining
Call if you need more
NEW Arista DCS-7504E-BND 7500E Series 7504E Switch Chassis Bundle
SKU: NSN-4811
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Arista DCS-7504E-BND 7500E Series 7504E Switch Chassis Bundle
SKU: NSH-7482
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days