Your search for "qsfp28" revealed the following:

Nvidia Mellanox MSN2010-CB2R 18x 25GB SFP28 4x QSFP28 F-B Air (C2P) Onyx Switch

SKU: NSB-6774
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Nvidia Mellanox MSN2700-CS2F 32x 100GB QSFP28 B-F Airflow (P2C) Onyx Switch

SKU: NSB-6731
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW nVidia Mellanox MSN3700-CS2R 32x 100GB QSFP28 F-B Airflow (C2P) Onyx Switch

SKU: NSN-9639
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Nvidia Mellanox MSN2100-CB2R 16x 100GB QSFP28 Front-to-Back (C2P) Onyx Switch

SKU: NSB-6762
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Cisco NCS-5501 NCS 5500 48x 10GB SFP+ 6x 100GB QSFP28 Router

SKU: NSB-7539
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Extreme 10401 100GB BASE-SR4 850nm MMF MPO QSFP28 Transceiver

SKU: NSB-5517
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Cisco N9K-C93240YC-FX2 48x 25GB SFP 12x 100GB QSFP28 F-B Airflow Switch

SKU: NSN-8186
Condition: New
Shipping: Overnight Options
Warranty: 365 days

NEW Arista DCS-7260CX3-64-R 64x 100GB QSFP28 2x 10GB SFP+ B-F Airflow Switch

SKU: NSN-0676
Condition: New
Shipping: Overnight Options
Warranty: 365 days

NEW Dell Z9264F-ON-RA EMC Z-Series 64x 100GB QSFP28 B-F Air OS10 Switch

SKU: NSN-0188
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Extreme Brocade BR-SLX-9240-32C-AC-F 32x 100GB QSFP28 F-B Airflow Switch

SKU: NSB-4670
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days