Your search for "c3850-nm-4-1g" revealed the following:
Cisco C3850-NM-4-1G Catalyst 3850 Series 4x 1GB SFP Switch Module
SKU: NSH-1156
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 18.99
• Only 1 remaining
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NEW Cisco C3850-NM-4-1G Catalyst 3850 Series 4x 1GB SFP Switch Module
SKU: NSN-1713
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 97.99
• Only 2 remaining
Call if you need more