BOOST Products Aluminum Elbow 180 Degrees with 4" (101mm) OD, Mandrel Bent, PolishedThe polished aluminium elbows are already beaded to allow an easy connection with silicone hoses. With these elbows, air charge piping or intakes are easily constructed. The elbows are also very suitable for welding with their 1,5mm wall thickness. Please notice that we offer a comparatively strong wall thickness. Many competitors use thin aluminium that cannot resist common boost pressures to save on expenses.