1.Light Duty Welding Blankets(13 ~ 18OZ) 2.Medium Duty Welding Blankets (20 ~ 30OZ) 3.Heavy Duty Welding Blankets(30 ~ 50oz) ... are needed. -Light Duty Welding Blankets(13OZ to 18OZ) - general purpose welding, light sparks, minimal spatter-Medium Duty Welding Blankets (20OZ ... to 30OZ)- heavier welding, sparks, spatter, light slag-Heavy Duty Welding Blankets (32OZ to 50OZ)- heavy sparks, spatter, ...