This likely refers to a stereo audio mix, providing two channels of audio. While not as immersive as 5.1 or 7.1 surround sound, a well-mastered stereo track can still offer clear and engaging audio.

If you're new to Prison Break, here's what you can expect from Season 1:

Michael didn't build the escape in one day. He chipped away. Piece by piece. Episode by episode. 71% of a plan was still a plan. Aris looked at his father's case file—a 412-page PDF he'd managed to scrape from a broken court server. He was missing 29% of the evidence.

(like commentaries or deleted scenes) typically found on the original Blu-ray