Your search for "QSFP28" revealed the following:

NEW Dell S4148F-ON-RA 210-ALSR 48x SFP+ 4x QSFP28 2x QSFP+ B-F (No OS10) Switch

SKU: NSN-9931
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Juniper QFX5210-64C-DC-AFO 64x 100GB QSFP28 F-B Airflow (DC) Switch

SKU: NSH-8263
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Cisco UCS-FI-6454 UCS 6454 18x 25GB SFP28 2x 100GB QSFP28 Interconnect

SKU: NSN-9197
Condition: New
Shipping: Overnight Options
Warranty: 365 days

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

NEW HPE Aruba JL624A 48x 25GB SFP28 8x 100GB QSFP28 Front-to-Back Airflow Switch

SKU: NSN-3639
Condition: New
Shipping: Overnight Options
Warranty: 365 days

NEW HPE Aruba JL704C 44x 25GB SFP28 6x 100GB QSFP28 F-B Airflow Switch w/ MACsec

SKU: NSN-2050
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Dell S4148U-ON-RA 48x (24x Unified) SFP+ 2x 40GB QSFP+ 4x QSFP28 B-F OS10 Switch

SKU: NSB-6545
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Dell S4148T-ON 48x 10GB Copper 2x 40GB QSFP+ 4x 100GB QSFP28 F-B OS10 Switch

SKU: NSN-1907
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Juniper EX4650-48Y-DC-AFO 48x 25GB SFP28 8x 100GB QSFP28 F-B Airflow Switch

SKU: NSH-8962
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Dell S5224F-ON-RA 24x 25GB SFP28 4x 100GB QSFP28 B-F Air No OS10 Switch

SKU: NSB-9767
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days