The BBJ SpeediDuct Trunking is easy to install and adds the finishing touches to an air conditioning installation by covering up unsightly pipework or wiring to give a clean white finish. This quality plastic trunking is fire resistant and weatherproof meaning it can be used internally or externally. This 105mm Duct range is for pipe sizes up to 3/4" and 7/8" with 13mm insulation.