The Parallax PS/2 Optical Mouse is a compact, low-profile, optical mouse with three buttons and a scroll wheel. Its small size and PS/2 connection make it a great input device for the Propeller Chip, SX or even the BASIC Stamp (with appropriate serial encoder chip).

NOTE: "This mouse is designed for use with the Parallax Propeller Chip and is not guaranteed to function with any other systems, including PCs.”