Minimum caliber for Limited 10 division is 9mm, however, most competitors use .40 or .45. Pistols can be either singles stack or "double-stack", single action autos.  Competitors are limited to 10 rounds in each magazine after the start signal.  Optical  or electronic sights are not allowed.  Compensators and/or barrel ports are not allowed.  Race-type holsters are allowed and there are no restrictions on position of holsters and magazine pouches.  Brands used are the same as those listed for Limited.  This is the "stock-car" of practical shooting.