Hi bucknyl,
Dell Inspiron 3521 is customized with the following single band (2.4GHz) cards.
- Intel® Centrino Wireless-N 2230 WLAN/BT Half Mini-Card.
- Dell Wireless 1703 WLAN/BT Combo Half Mini-Card.
- Dell Wireless 1704 WLAN/BT Combo Half Mini-Card.
We will not be able to replace the card with upgraded dual band WLAN card on the system.