Flask is made of pure titanium without lining and premium coating. It is tasteless, odourless and non-toxic. Originally designed for hiking, this flask is and remains practical in all circumstances. Titanium is ultra-light and super strong; it is environmentally friendly, biocompatible and bacteria-inhibitive; it is also extremely hypoallergenic and exceptionally resistant to corrosion. Keith is an ISO 9001:2008 certified company (accredited by the NAC, FIA member). It is also a GMC certified manufacturer (tested by TÜV Rheinland). Keith titanium produces successful samples from the German EU Food Grade German (LFGB) Test and the US FDA test (both by SGS). Keith Titanium USA is Keith's only authorized retailer on Amazon. Each Keith product is assigned a unique ID worldwide for quality control and customer service. Keith offers a lifetime original owner warranty on all products sold through authorized dealers against defects in materials and workmanship. Keith will repair or replace at its discretion any product with free of charge manufacturing defects. Damage caused by wear and tear and will be repaired at a reasonable price.