Sony Corp. unveiled a new e-book reader Thursday with a built-in light and a touch-sensitive display, features that set it apart from Amazon.com Inc.’s competing Kindle reader.

The PRS-700 is Sony’s third model of the Reader, and will go on sale at the end of the month for about $400. It represents further experimentation on the part of manufacturers trying to find the right formula to make e-book readers more than a niche product. Neither Sony nor Amazon have revealed sales figures for their readers.

Like the earlier models and the Kindle, the PRS-700 has a six-inch screen of “electronic ink,” which presents dark gray text on a light gray background. Unlike the liquid-crystal displays of laptops and cell-phones, e-ink displays cannot be lit from behind, but the PRS-700 has light-emitting diodes that can be turned on to illuminate the screen from the sides.

The 10-ounce device also comes with a stylus, which can be used to highlight text or make handwritten notes. It can hold 350 books in its internal memory, and more in a memory card.