The Buffalo Convention of December 10, 1908 established two future roll formats for the US-producers of piano rolls for self-playing pianos. The two formats had different punchings of 65 and 88 notes, but the same width (11+1⁄4 inches or 286 millimetres); thus 65-note rolls would be perforated at 6 holes to the inch, and 88-note rolls at 9 holes to the inch, leaving margins at both ends for future developments. This made it possible to play the piano rolls on any self-playing instrument built according to the convention, albeit sometimes with a loss of special functionality. This format became a loose world standard.