Abdominal exercise bench

An abdominal exercise bench comprising:

• an upper frame having at least two arched downwardly facing surfaces spaced apart, two openings defined by the arched surfaces, an upper flat elongate surface, a vertical pin hole in a central portion and a square opening in a lower central portion between said two semi-round openings;
• an auxiliary base shaped as an elongated rectangular plate, having an upper surface that slopes downwardly from an upper end to a lower end, a rectangular recess in an upper portion, a pin hole in the center of said rectangular recess, and a plurality of retainer holes in a lower portion for a plurality of retainers to pass through, a flat bottom surface and a plurality of square recesses in the bottom surface;
• a combining pin having a grip projection on top and a column extending downward and having an elastic gasket fitting around an upper portion and two opposite projections extending outward from a bottom end to conform to the pin hole in the upper frame;
• and
• said two semi-round openings of the upper frame capable of being passed through by two feet of a user, who can hook his two feet on said frame, said auxiliary base being temporarily adapted to be kept immovable by something such as a door, said user hooking his feet on said frame, sitting on the floor for making abdominal exercise.