9000 classic series chair, 4-leg, stackable, plastic seat with steel back support.
For replacement glides:
Models 9018 and 9016 use 1-1/8" outside diameter, part number F-8000V or F-8000-NV
Models 9014 and 9012 use 5/8" outside diameter, part number F-1626V or F-1626-NV
*If you have Virco's old style 9000 series, with tapered legs, 5/8" outside diamter, use part number F-3627V or F-3627-NV