On May 6, 2009, Amazon announced the Kindle DX. It is the first Kindle model with an accelerometer, automatically rotating pages between landscape and portrait orientations if the device is turned on its side. It is slightly over 1?3 inch (about 8.5 mm) thick, has a 4 GB (3.3 GB user-accessible) storage capacity, holding approximately 3500 non-illustrated e-books, and a 9.7 inch (24.6 cm) display with 1200 x 824 pixel resolution. __