The cassette was a great step forward in convenience from reel-to-reel audio tape recording, though because of the limitations of the cassette's size and speed, it initially compared poorly in quality. Unlike the 4-track stereo open reel format, the two stereo tracks of each side lie adjacent to each other rather than being interleaved with the tracks of the other side. This permitted monaural cassette players to play stereo recordings "summed" as mono tracks and permitted stereo players to play mono recordings through both speakers. The tape is 3.81 mm (0.150 in) wide, with each stereo track 0.6 mm wide and an unrecorded guard band between each track. The tape moves at 4.76 cm/s (1 7/8 in/s) from left to right. For comparison, the typical open reel format in consumer use was ¼ inch (6.35 mm) wide, each stereo track nominally 1⁄16 inch (1.59 mm) wide, and running at either 9.5 or 19 cm/s (3.75 or 7.5 in/s).