Toughened glass is glass strengthened by controlled heat treatment and is also called tempered glass. Nordic Lights commonly uses Tempered glass in work-light descriptions and may use Hardened Glass in some product data. It offers good scratch, heat, chemical, and UV resistance, but the specified lens material is product-specific. If broken, fully tempered glass generally fragments differently from ordinary annealed glass because of internal stresses created during manufacture. In work lights, the material can resist abrasion and harsh cleaning better than many uncoated plastics. Impact requirements, thickness, optical design, sealing, and replacement method must still be considered for the specific product.