Extended Robust Clamp with Security Knob ATV Mount & 4 Hole AMPS Adapter for Garmin Tread (sku 57296)Extended Robust Clamp with Security Knob ATV Mount & 4 Hole AMPS Adapter for Garmin Tread The design is perfect for off road vehicles. Designed to attach directly to your Garmin Tread GPS Antenna mount base. The robust clamp is a sturdy mount base with quick and easy attachment with a security knob. Clamp range Fits rails form 0. 25 inch 2 inch diameter. No tools needed for instillation. Includes an optional removable security knob. The 3. 75 inch