For 16mm tube. Omniflex® System Features: *Elastomeric polymer of the highest quality, as used on sailboard mast knuckles and industrial hinges. *Completely omni-directional in operation and capable of many millions of flexures without failure. *Your extension can be completely removed for security purposes or easily exchanged for another length, grip or colour without unscrewing it. *Screw holes pitch is identical to our existing stainless steel base so is interchangeable. *Saddle spacers convert the base to fit circular tillers of 25mm (1in.) and 32mm (1 in.) diameter.