Are the tubefittings suitable for outdoor or indoor use only?

For external use, we recommend the use of galvanized (silver) fittings. Tubefittings in black paintwork are powder coated, but they are not covered with a zinc layer, so we cannot give a 100% guarantee for long-term weather resistance. Natural tubeclamps, on the other hand, do not have any coating, they are raw. Natural tubeclamps are easy to paint or they can be used in highly designer projects in which the customers want to achieve the effect of rust and corten steel.