Your search for "QSFP28" revealed the following:

NEW Cisco N9K-X9636C-R Nexus 9500R Series 36x 100GB QSFP28 Switch Line Card

SKU: NSN-8304
Condition: New
Shipping: Overnight Options
Warranty: 365 days

NEW Juniper QFX5120-32C-AFI QFX5120 Series 32x 100GB QSFP28 B-F Airflow Switch

SKU: NSN-3712
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

Nvidia Mellanox MSB7700-ES2R SB7700 36x 100GB QSFP28 EDR F-B Air Switch

SKU: NSB-9560
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Cisco NCS-5001 NCS 5000 Series 40x 10GB SFP+ 4x 100GB QSFP28 Router

SKU: NSH-9287
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

Dell E3248P-ON 48x 1GB PoE+ RJ45 4x 10GB SFP+ 2x 100GB QSFP28 F-B Air Switch

SKU: NSB-9278
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Dell S5232F-ON EMC S 32x 100GB QSFP28 2x 10GB SFP+ F-B Air No OS10 Switch

SKU: NSN-9942
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Arista DCS-7280SR2-48YC6-F 48x 25GB SFP28 6x 100GB QSFP28 F-B Airflow Switch

SKU: NSH-8383
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Extreme VSP7400-32C-AC-R VSP 7432CQ-R 32x 100G QSFP28 B-F Airflow Switch

SKU: NSN-3549
Condition: New
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