How to know a bulb will be OK vertical?

[ibjamming]

I want to go vertical this round but I've heard that some bulbs aren't made for vertical use. How do you know a bulb can be run vertical? It doesn't say anything about either horizontal or vertical on the box. Does it ALWAYS say "horizontal only" if that's the case?

Thanks...

 

[PermaBuzz]

Its usually horizontal that can cause problems.
Any bulb oughta be ok vertical.

 

[TheShroomDude]

It is the Mogul that you have to look at not the bulb.

 

[ScrubNinja]

Somewhere on one of the parts, I forget which, look for an inscription. From a post by DiscoBiscuit: "V indicates vertical. U indicates universal (either way). No indication, probably universal."

 

[boroboro]

Isn't this only the case with MH / CMH bulbs? I thought I read somewhere that all HPS bulbs are universal mount.

 

[silent_lemon]

Isn't this only the case with MH / CMH bulbs? I thought I read somewhere that all HPS bulbs are universal mount.

i was told this EXACT thing at my favourite hydro shop.

 

[Bush Dr]

There USED to be a difference, but all lamps made since 2006 are universal mounting

 

[boroboro]

There USED to be a difference, but all lamps made since 2006 are universal mounting

HPS and MH? I've only bought CMH and HPS bulbs recently. All the HPS I've encountered have been universal mount. CMH, though, distinctly comes in Vertical or Horizontal mount:
http://advancedtechlighting.com/cdmed18.htm

Haven't bought one, but it seems like MH can be position-specific as well:
http://www.specialty-lights.com/10245.html

There. Clear as mud now?