4 foot strip light shroud? What's the term?

I'm after a strip light unit of about 4 feet that can take say 2 - 4 tubes totalling around 400w

Does anyone know the term for the unit the tubes go in so I can stop ripping my hair out searching lol

Also, if anyone also knows good veg & flower tubes in that size please say so.

Peace

Also looking for those twin bulb bayonet fittings! Can't even find the damn things on Ebay!