You need 2 tennis balls. :)
You need very sharp box cutters.
When you slice the tennis balls be very careful - slow incision - and start small with X figure.
Make sure that you can squeeze the ball and hope that it fits over the walker leg.
Leave the manufacturer rubber stoppers and pull the tennis ball over the leg.
This is the manufacturer stopper and in the back you can see the tennis ball on the opposite leg.
Voila!! Done and done. & happy holidays. Check out my clothing line. TrimIncClothing : com