STANDARD AMPS PATTERN - 2-Hole base plate fits popular AMPS pattern devices. 48.5 mm (1.91") distance between holes, center to center. ALL METAL CONSTRUCTION - All metal 20mm ball and AMPS plate ensures a strong base for your application. ENDURO READY - Familiar 20mm ball works with all of our Enduro series components which connect to a ball. ABOUT TACKFORM - We're a small family owned business in the Chicago suburbs. Any questions or concerns, contact us immediately for a rapid response from our support team. NOTICE! - Due to a such a broad range of mounting options (M4, M5, 10/32, self tapping, etc) we do not include dash/surface mounting hardware.Â