Your search for "Dell S4820T" revealed the following:
NEW Dell S4048-ON 48x 10GB SFP+ 6x 40GB QSFP+ Front-to-Back Air 210-ADUW Switch
SKU: NSN-1862
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S5248F-ON 48x 25GB SFP28 2x QSFP28-DD 4x QSFP28 F-B No OS10 Switch
SKU: NSN-9940
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148U-ON 48x 24x Uni SFP+ 2x QSFP+ 4x QSFP28 F-B No OS10 Switch
SKU: NSN-9962
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148T-ON-RA 48x 10GB Copper 2x 40GB QSFP+ 4x QSFP28 B-F OS10 Switch
SKU: NSN-8125
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148T-ON 48x 10GB Copper 2x 40GB QSFP+ 4x QSFP28 F-B No OS10 Switch
SKU: NSN-9964
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Dell S4148FE-ON-RA 48x 10GB SFP+ 2x 40GB QSFP+ 4x QSFP28 B-F No OS10 Switch
SKU: NSB-9791
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148FE-ON 48x 10GB SFP+ 2x 40GB QSFP+ 4x QSFP28 F-B No OS10 Switch
SKU: NSN-9966
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Dell S4148FE-ON 48x 10GB SFP+ 2x 40GB QSFP+ 4x 100GB QSFP28 F-B No OS10 Switch
SKU: NSB-9790
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Dell S4148U-ON 48x 24x Unified SFP+ 2x QSFP+ 4x QSFP28 F-B OS10 Switch
SKU: NSN-3864
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Dell S4148FE-ON 48x 10GB SFP+ 2x 40GB QSFP+ 4x 100GB QSFP28 F-B Air OS10 Switch
SKU: NSH-9213
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days