PolyJet 3D printing works by jetting layers of curable liquid photopolymer onto a build tray, similar to how an inkjet printer jets ink onto paper. UV curing bulbs are located next to the jetting heads to cure each layer as the material is applied. PolyJet is capable of applying multiple colors and durometers of material in the same build, which makes it unique. This technology can produce exceptional detail, surface smoothness, and precision. PolyJet printing is ideal for cosmetic and aesthetic applications. It is not quite as rigid as SLA or FDM, however, and thus not always an appropriate choice for models that need good structural strength.