1PCS Clamped Round Tube Mount Base 1.5", Ball Head Double U-Clamp Base
 

 

product manual: 

 

Clamps tubing from 19-31mm diameter
Clamps 20-28mm diameter tubing
Clamps 12-18mm diameter tubing
    
 

Packing:1PCS
Warranty period: 120 days
DataCaciques