SnapIt! Wheelchair Small Drink Holder Wheelchair/Walker/Rollator/Scooter Drink Holder sized for canned drinks and plastic 20 oz. soft drink bottles. I.D. 2.9" Overall Height 3.95". Includes SnapIt! System MultiMount Bracket with hardware for attachment to 3/4", 7/8", 1", 1 1/8" and 1 3/16" round tubing commonly found on mobility assistance devices. Snap in clip on SnapIt! System MultiMount Bracket is designed to fail in the event of accidental contact with a hard surface in order to protect the drink holder from damage. Technical Specifications SnapIt! Tubing Diameter Size Chart Fractions Decimals Metric Flat Length 3/4" .75" 19mm 2.356" 7/8" .875" 22mm 2.75" 1" 1" 25mm 3.142" 1-1/8" 1.125" 29mm 3.53" 1-3/16" 1.1875" 30mm 3.73" 1-1/4" 1.25" 32mm 3.927" Step 1) Find a piece of paper measuring at least 4" x 1" Step 2) Now wrap the piece of paper around the section of tubing you would like to mount your SnapIt! cup holder. Step 3) While the paper is wrapped around the tube, mark the end of the piece of paper with a pencil. This will measure the entire circumference of the tube. Step 4) Now measure from the end of the paper to the mark with a ruler. Step 5) Look at the table above. Find the "Flat Lenght" and it's correlating "Diameter in Fractions", "Diameter in Decimals" and "Diameter in Metric" Now you will have the diameter of the tube!