Question about T5HO lights

[camille1585]

After deciding that the Ikea led strip may not be a very good led, I've been looking at T5HO fixtures. I have a really dumb question: what makes it high output, the ballast/fixture or the bulbs, or the combination of both? I ask this because a french grow-shop site I found sells a 2 bulb 2ft fixture but without bulbs. When I go to the bulbs section of the site, I find T5 bulbs, but no T5HO specifically.

Alternatively I found another site selling a 1 bulb Sunblaster T5HO , but no replacement bulbs for down the road, leaving me with the same question.

As I search I've very surprised by how little there is in the way of non MH or HPS lighting. Seems like every single site is aimed predominantly at weed growers. I even went to lurk on an EU-UK orchid forum in the under lights section for ideas, and it seems that many people use MH for their orchids, rarely fluorescents...