 These modes were also outright incompatible with some monitors, producing display problems such as picture detail disappearing into overscan (especially in the horizontal dimension), vertical roll, poor horizontal sync or even a complete lack of picture depending on the exact mode attempted.Due to these potential issues, most VGA tweaks used in commercial products were limited to more standards-compliant, "monitor-safe" combinations, such as 320×240 (square pixels, three video pages, 60 Hz), 320×400 (double resolution, two video pages, 70 Hz), and 360×480 (highest resolution compatible with both standard VGA monitors and cards, one video page, 60 Hz) in 256 colors, or double the H-rez in 16-color mode.Several companies produced VGA compatible graphic board models.