Your search for "dell s4820t" revealed the following:
NEW Dell S5212F-ON-RA 12x 25GB SFP28 3x 100GB QSFP28 B-B Air No OS10 Switch
SKU: NSN-9951
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Dell S5212F-ON-RA 12x 25GB SFP28 3x 100GB QSFP28 B-B Air No OS10 Switch
SKU: NSB-9769
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Dell Brocade DL-320-0005 300 Series 24x 8GB FC (16x Active) SAN Switch
SKU: NSH-6768
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days