Product Content: You will receive 2 sets of rollator walker replacement knobs. One pack contains two sets, including 2 screws, 2 washers, and 2 knobs, enough quantity for your daily replacement. Product Size: The size of our drive rollator knob measures about 4.4cm/1.7in. The diameter of the washer measures about 1.9cm/0.75in. Thoughtful Design: The rollator knob replacement is designed in the shape without sharp corners and has a soft touch. You can easy to grasp, assemble and use. Easy to Assemble: You can assemble the rollator parts just by your hands, no use to apply any tools. Just put the hex bolt through the rollator frame, insert the plastic washer, install the knob on the outside hex bolt, and then tighten the knob. Compatibility: Universal design of our rollator walker part is compatible for most rollators and rolling walkers of various brands. Don't worry about the compatibility.