Your search for "N20-CBLKB1" revealed the following:

Cisco N20-CBLKB1 Single Slot Blade Blanking Panel for UCS 5108 Server

SKU: NSH-7697
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Cisco N20-CBLKB1 Single Slot Blade Blanking Panel for UCS 5108 Server

SKU: NSN-7222
Condition: New
Shipping: Overnight Options
Warranty: 365 days