lamp shape

[JJWalecka]

What's the difference between a BT37 lamp
And a ed37 lamp?
The shapes are ddifferent but anything else?

 

[LEO2854]

What's the difference between a BT37 lamp
And a ed37 lamp?
The shapes are ddifferent but anything else?

Bulb Shape: BT37

Looks like the ED37 is a protected arc tube..http://genet.gelighting.com/LightProducts/images/t04/0000000/r00021v-1.pdf