Description With the use of 10 rollers these wheels have the ability to drive forward and laterally. Available in 3" and 4" sizes compatible with TETRIX PRIME What you will get two 4〃Omni Wheel four Button Head Cap Screws one Spacers Specifications Size: 4" Outside Diameter: 4" Inside Diameter: 8 mm Quantity: pkg of 1 Material: metal wheel with Neoprene rubber rollers Weight: 323 grams per wheel and tire