A compression mechanism can include a first scroll member, a second scroll member, and an Oldham coupling. The first scroll member can include a base plate. The second scroll member can meshingly engaged with the first scroll member, and include a first radially extending slot. The Oldham coupling can include a ring portion disposed about the base plate and a first radially extending key portion disposed in the first radially extending slot. The ring portion and the key portion can include a pair of upper surfaces and a pair of lower surfaces. At least one pair of upper surfaces or lower surfaces can be substantially coplanar.