The UV lightbox used by Australian researcher Hart, as described in the study on keratinocyte viability, emitted light in the 365-405 nm wavelength range, according to a study published on Nature.com. This specific range falls within the UVA spectrum, which is known for its effects on cell signaling. The study used this light source, emitted by a nail drying machine, to investigate the impact of UV radiation on human skin cells (keratinocytes).