Suitable for size 42/43. Slippers are a type of shoe with a completely empty heel and only a toe in the front. They are mostly flat-soled and the material is often quite light and soft. The size of furry slippers will increase after wearing them due to material problems. Merchants often indicate the shoe size range. 42-43 means suitable for 42/43 code. Shoe size, also commonly referred to as shoe size, is a standard system of units used to measure the shape of the human foot for fitting shoes.