Designed to fit on externally butted seat tubes with an OD of 29.4mm but can easily be filed to fit a smaller or larger OD.
 
Made in Australia from 316 Stainless Steel using an M5 Stainless Steel bolt with a replaceable brass nut and weighing in at approximately 22grams. 
 
Recommended to use 56% silver and flow through the small hole in the middle of the slot to reduce final cleanup.