Here is a simple and effective way to level wobbly furniture. Each leveller comes as a pair of interlocking shims that are adjustable to give you exactly the height you need to fill a gap up to 1/2". They are made of thermoplastic elastomer, which feels just like rubber. Once in place, tiny nubs keep the leveller from slipping, even on smooth surfaces. Each shim is a 2" × 1 3/4" diameter oval.