You need specific S Pen or S Pro pen for Galaxy Z Fold 4

You will get 512GB storage with this Z Fold 4

The frame is build of Armor Aluminum protect by Corning Gorilla Glass Victus+

263 gm weight to makes you comfortable

You don't have to worry about accidentally getting your phone wet because you have IPX8 water resistance protection

After got fold its dimension became 67.1 x 155.1 x 14.2- 15.8mm

When unfolded, the dimensions remains 130.1 x 155.1 x 6.3mm

7.6 inch QXGA+ unfold display and with cover 6.2-inch HD+ Dynamic AMOLED 2X

With 12GB RAM you will have three options as 256GB, 512GB, 1TB