Transform your vehicle's speedometer system with the Speedhut SPEEDBOX, a versatile mechanical drive speedometer converter that bridges classic and modern technology. This innovative solution accepts both GPS and modern transmission signals while maintaining compatibility with cable-driven mechanical speedometers. Installation is remarkably straightforward, requiring just 12 volts and ground for a true plug-and-play experience. The unit features a 7/8-18 drive output thread and 0.112-inch square, accommodating various speedometer configurations. With an impressive calibration range of 170-1650 turns per mile and a default setting of 1000 turns per mile for US speedometers, it delivers precise speed readings without complex setup procedures. The included GPS antenna enables automatic calibration, while the compact design allows for dashboard mounting. Say goodbye to complicated calibration processes and subscription fees - the SPEEDBOX delivers reliable performance right out of the box.