Have I Hit A Jackpot Or Junk Pile? lol

ok Basically i have stumbled upon a bunch of lights .....im sure they are MH as it says ..but will these be efficient for flowering...will this light make a higher yeild .... also how many plants will this one light support....i have access to many many many more of these ...how many should i get? how many should i use? using these alone during flowering will they be efficient? ...not sure...thats where ya all come in .. im gonna attach pics of these lights...they say for outdoor use only but thats only a warning right? lol can use them inside for growin? All tips/comments are welcomes

MH lights are great for getting your plants started in the veggie stage. They makes your plants short & stalky. Not good for flowering BUT you can get a HPS conversion bulb and put it in for the flowering period. You might have a heat problem if you put that thing in a closet. Be sure to provide plenty of ventalation. Here's my set up, a 400 watt HPS with a 280 CFM exhaust fan hooked to it.