Abstract: The herein disclosed technology provides a roller therapy device including a ball and a dual-component casing with components that mate together on opposite sides of the ball to rotatably secure the ball. In one implementation, the dual-component casing includes a cap portion with a cavity sized and shaped to receive the ball and an annular portion that can be selectably attached to and detached from a mouth of the cavity after the ball is positioned in the cavity. When connected in such manner, the ball protrudes through and aperture in the annular portion and is freely rotatable relative to the dual-component casing.