These tables are intended for air with air as a decompression gas. For advanced Nitrox divers, they also offer an optional accelerated programmed decompression (highlighted in green) using 75% Oxygen at the last two stop depths. These tables are based on Bühlmann's ZH-L16 algorithm. Many divers prefer the Bühlmann algorithm over that of the US Navy. However, repeated grammatical groupings are not transferable to ANY other table, including US Navy tables.