Bar clamp fits Yamaha V Star handlebars or any 26mm diameter handlebars. Add a strip of thin foam between handlebar and clamp to keep snug and prevent slipping. Holder holds iPhone 6 Plus with no case or using a UAG case, probably any case that does not exceed 83mm X 161mm Tested and handle bumps great on my bike.Print at 45% honeycomb infill, solid diaphragm every 20 layers. Don't remember the size bolts for the clamps, maybe M5 If you need any adapters or extensions between the pieces, build them here: http://www.thingiverse.com/apps/customizer/run?thing_id=62800