I believe there HPS ballast orientated. Its neither one or the other like u stated, But what i have seen there HPS. A switchable ballast is out of the question becuase they use either one or the other and its 2bulbs in one. I think people have noted that these bulbs arent really all that good, they have high output on the spectrum where u dont need it and where u do. If u havent gotten anything yet, i would go with a switchable ballast, there more $$ but two in one. so kinda less. and u will utilize both bulbs to the fullest.