Data Collector Pole Clamp with Compass and Phone Holder Universal Portable GPS RTK Pole Clamp Holder1[Universal Fit] This pole clamp is designed to accommodate poles with diameters of 32mm or 20mm, ensuring compatibility with a wide range of surveying equipment. 2[Anodized Aluminum] Constructed from anodized aluminum, this pole clamp offers excellent stability and durability in the field, providing reliable support. 3[Quick Release Mount] This clamp holder is compatible with the most popular quick release mount, allowing for easy installation and removal. 4[Practical Tool] Specifically designed for RTK measurements that require a pole and a data collector, this pole clamp is an ideal solution, offering secure mounting for your equipment during surveying tasks. 5[With Compass] Equipped with a compass, this pole clamp provides added functionality, allowing for easy orientation and direction finding while you conduct your RTK surveys.