Umbrella mount is designed for 2"x2" (50.8 x 50.8mm) posts. Bolt is ¼" (6.35mm) diameter by 3 ½" (89mm) length with a matching nut and washer. Umbrella pole hole is 40mm (1.57").

Printed in ABS with, 5-6 perimeters/walls, 15-20% infill and 4-5 top/bottom surfaces.

STEP files are uploaded but I can export whatever file type is required (assuming OnShape supports that type).