Hey, a) please find the customization options for the NextBox at the shop: https://shop.nitrokey.com/shop/product/nextbox-116 . in short: up to 2TB. b) you can indeed extend with external storage although this comes with some limitations due to the USB power available through the Raspberry PI, see our documentation for more details: https://docs.nitrokey.com/nextbox/faq/hardware.html