Key Specification: Membrane switch (3.8 mm stroke, soft snap) Cylindrical step sculpture 19.05 mm pitch Interface:USB (with 2 downstream ports -100mA- on the back) Compatibility:IBM PC or Mac compatible personal computer with USB interface Size:11.6 (W) x 4.7 (D) x 1.5 (H) [inch] *excl. protrusions Weight:1.43Lb, 680g (incl. cable)