Your search for "qsfp28" revealed the following:
NEW Dell S4112T-ON-RA 12x 10GB Copper 3x 100GB QSFP28 B-F AC (No OS10) Switch
SKU: NSN-9955
Condition: New
Shipping: Overnight Options
Warranty: 365 days
NEW Dell N3248P-ON-RA 48x 1GB PoE RJ45 4x 10GB SFP+ 2x QSFP28 B-F OS6 Switch
SKU: NSN-9976
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Extreme 10410 0.5m 100 Gigabit QSFP28 Direct Attach Copper Cable
SKU: NSB-4918
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Dell Z9264F-ON-RA EMC Z-Series 64x 100GB QSFP28 Back-to-Front Air OS10 Switch
SKU: NSB-7049
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Juniper ACX6360-OR-AC 20x 100GB QSFP28 8x 200GB CFP2- DCO F-B Air Router
SKU: NSH-8437
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Cisco C9500-32C-E Catalyst 9500 32x 100GB QSFP28 Front-to-Back Air Switch
SKU: NSN-3657
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Juniper EX4650-48Y-DC-AFI 48x 25GB SFP28 8x 100GB QSFP28 B-F Airflow
SKU: NSH-8961
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Nvidia Mellanox MSN2410-BB2F 48x 10GB SFP28 8x QSFP28 B-F Air Onyx Switch
SKU: NSN-9264
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Nvidia Mellanox MSB7890-ES2R 36x 100GB QSFP28 Front-to-Back (C2P) EDR Switch
SKU: NSB-6792
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
Dell N3248TE-ON-RA 48x 1GB RJ45 4x 10GB SFP+ 2x 100GB QSFP28 B-F Air OS6 Switch
SKU: NSB-8628
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days