Your search for "cab-stack-3m" revealed the following:

Cisco C2960X-HYBRID-STK FlexStack-Extended Hybrid Module for 2960X and 2960XR

SKU: NSH-9057
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

NEW Cisco WS-C2960XR-48FPD-I 48x 1GB PoE RJ45 2x 10GB SFP+ Switch

SKU: NSN-2178
Condition: New
Shipping: Overnight Options
Warranty: 365 days