and PRS-505 offered no way for the user to annotate a digital book since those lack a keyboard. This was addressed by the release of the PRS-700. Improvements of PRS-700 vs. the PRS-505 include the following: The 6-inch E Ink display (same resolution as before) is now a touch screen, removing the need for the 10 side buttons. Note taking and virtual keyboard, made possible by the touch screen. Page turning buttons remain but can also be accomplished by touch screen gestures. LED lighting for use in poor lighting conditions. Internal storage is doubled to 512 MB. PRS-700 specifications Size: Approx. 174.3 × 127.6 × 9.7 mm (6" × 5" × 0.4") Weight: 283.5 g (10 oz) Display: size: 15.5 cm (6 in) diagonal (approx 1/4 area of letter-sized page) resolution: 170 dpi, 8-level gray scale integrated touchscreen Memory: 512 MB standard (350 eBooks at 1.2 MB each average, 420 MB available), Sony Memory Stick Pro Duo 8 GB, SDHC card expansion up to 32 GB Lithium-ion battery, up to 7500 "page turns" per charge PC Interface: USB port 2.0 Built-in LED reading light 2007 Model (Discontinued late 2009) PRS-505 The PRS-505 was launched on 2 October 2007, a software and hardware updated version of the PRS-500 Reader, which it replaced. The 505 keeps the 6" E Ink display of the original Reader, but uses an improved version of E Ink Vizplex imaging film with faster refresh time, brighter white state, and 8-level grayscale. The PRS-505 is thinner than its predecessor (8 mm vs. 13 mm) and comes with more internal memory (256 MiB vs. 64 MiB). Other new product features included auto-synchronization to a folder on a host PC, support for the USB Mass Storage Device profile, and full USB charging capability (the PRS-500 could only be recharged via USB if the battery was not fully drained, and if the Sony Connect Reader software was installed on the host PC). Also, adding books to "Collections" (a feature to organize and group book titles) is now possible on the storage card, unlike the PRS-500 model. Version 1.1 firmware, available as a free download since July 24, 2008 adds support for the EPUB format, Adobe Digital Editions 1.5 and Adobe DRM protected PDF files, automatic reflow of PDF files formatted for larger pages enlarges the text to improve readability, and support for high capacity SDHC memory cards. Specifications Size: 175 ×