The outer globe for a MH bulb is made to stop UV from exiting the bulb. BUT if the outer globe is broken you will cook the hell out of you plants. And if stupid enough to be in the same room when when one lights of. YOU will get to see the doctor after a few weeks, cause he will take the blind folds off you eyes.
Friend got to close to a uv lamp and " its like having sand in you eyes and you wife gets to drive you around.
merk lights are way off in the total specturm, cheap but worthless.