Your search for "OSFP-400G-FR4" revealed the following:
Arista OSFP-400G-FR4 400GB BASE-FR4 1310nm 2km SMF LC DOM OSFP Transceiver
SKU: NSB-5211
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 705.99
• 11 in stock
Call if you need more
NEW Arista OSFP-400G-FR4 400GB BASE-FR4 1310nm 2km SMF LC DOM OSFP Transceiver
SKU: NSN-6699
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 1,469.99
• 7 in stock
Call if you need more
NEW Arista QDD-400G-FR4 400GB BASE-FR4 1310nm SMF 2km QSFP-DD Transceiver
SKU: NSN-6734
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 437.99
• Only 2 remaining
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Arista QDD-400G-FR4 400GB BASE-FR4 1310nm SMF 2km QSFP-DD Transceiver
SKU: NSB-5245
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 429.99
• Only 2 remaining
Call if you need more
Arista OSFP-400G-2FR4 400GBASE-2FR4 Duplex CS SMF 2km DOM OSFP Transceiver
SKU: NSB-5212
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
NEW Arista OSFP-400G-2FR4 400GBASE-2FR4 up to 2km over 2x pair duplex SMF OSFP
SKU: NSN-6700
Condition: New
Shipping: Overnight Options
Warranty: 365 days