Duroflex Insulated is manufactured using Aluflex as the inner core, wrapped in a polyester insulation blanket with the outer skin / vapour barrier in a durable AL-PET spirally wound sleeve. This flexible is very durable and ideal for making final connections to diffusers and other outlets or inlets of air conditioning systems. Due to the fact that the AL-PET material is used in both the core and the outer sleeve the flexible is fire rated and has been tested and certified to be SANS 10177-3: 2005 Class 3 fire rated.