This is bright, very bright and as to be expected in a small flashlight it gets hot quick, really quick. In 75 degree surrounding ambient temp this was too hot to handle in turbo mode by the 1 minute 30 second mark. And it was stepping down, I would say roughly in 1 minute 30 seconds it had stepped down about 1000 lumens to approximately 3200 – 3500 lumens. That is not bad for a light of this small physical size. In turbo and high this will step down to 1200 lumens (by Imalent manual). Note: all the lumens measurements I mentioned are just my best guess, I did not have equipment to measure the light output. Real world observations remember? Take with a grain of salt.