Hello Klarus Flashlight friends, I'm from Brazil and I bought a Klarus XT21C flashlight a year ago on Aliexpress and now it was defective, and the seller didn't respond to my request to activate the warranty. This way, I am contacting the people at the factory directly to request an exchange of the product or a repair of the flashlight. The defect that the flashlight has is that it does not turn off. The lantern never fell to the ground and never took any knocks. Thank you very much in advance for your kindness in responding to my request. Yours sincerely, Oliveira