Patent ID: 7575540

Claim:
The exercise ball riser for elevation in combination with a semispherical ball having a rigid base plate of a predetermined diameter, the riser for elevating the ball comprising: a first portion extending in a longitudinal direction of the riser, said first portion having an outside diameter and an inside diameter dimensioned for receiving the predetermined diameter of the rigid base plate; a second portion adjacent said first portion and extending in the longitudinal direction of the riser, said second portion having an inside diameter, said inside diameter of said second portion being smaller than said inside diameter of said first portion thereby defining a shoulder therebetween, said shoulder being configured for supporting the base plate; a third portion adjacent said second portion and extending in the longitudinal direction of the riser, said third portion having outside diameter being larger than said outside diameter of said first portion for defining a collar about a circumference of the riser, said third portion having a base surface, and said third portion having an inside diameter being greater than said inside diameter of said second portion for defining an undercut of said shoulder.