The ISO Taper Shank is the classical version used in machine tools with automated tool exchange. DIN 69871 is compatible with CAT systems as they have the same taper and the collar size is equal. DIN 69871 have an extra V shape cut on the colar than the CAT system that is mostly used for clamping position.
DIN 69871/CAT systems are mostly used in North America, while MAS-BT is mostly used in Europe.
Models are available with central cooling (form A/D), with cooling over the flange (form B) or as combined version (form AD/B).