The answer is yes HTG made 600 watt ballasts & they still make 600 watt ballasts,HTG is the largest grow supply in the world because they make top quality grow gear at affordable prices.
I run 8 flood & drain tables,each table is light with 3 of htg's 600 watt digital light/ballasts & they have been operating trouble free through many grows,the 600's come with a 5 year guarantee as well.
One thing,why wouldnt you just went to htg's web site to see if the ballasts were made by htg ? You should atleast visit the site to check how much they cost brand new so your friend dont over charge you.
I would only pay 50 cents on the dollar for them & even less if there isnt atleast one year left on the warranty,a magnetic 600 watt ballast is worth about $50 used & a digital 600 watt ballast is only worth $75 & thats if there is still 3 years or more left on the warranty.
FYI,htg will sell you a brand new 600 watt digital ballast,plus a massive 30 inch x 36 inch air cooled reflector,all power & connection cords plus a new bulb,then ship the complete package to your door for $320 & thats for a complete plug n play system,now you see why i say the used gear is worth so little.
