Your search for "cfp2-100g-er4" revealed the following:
Cisco CFP2-100G-ER4 100Ğ BASE-ER4 1310nm 40km DOM CFP2 Transceiver
SKU: NSB-2465
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 6,187.99
• Only 2 remaining
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Cisco A9K-MPA-2X100GE ASR 9000 Series 2x 100GB CPAK Modular Port Adapter
SKU: NSH-6777
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 2,989.99
• Only 2 remaining
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NEW Cisco A9K-MPA-1X100GE ASR 9000 1x 100 Gigabit CPAK Modular Port Adapter
SKU: NSN-2417
Condition: New
Shipping: Overnight Options
Warranty: 365 days