Mathmos Fluidium Bulb?

[Leedsboi86]

Hey Everyone!

What bulb do I need for this lamp?

I bought a R50 40W E14 but the bottle won't fit into the base properly with this in.

Also have a R39 30W which fits but sadly doesn't give enough heat.

Whats the exact bulb I need? Someone told me a Halogen E14 40W

The lamp doesn't have a heat shield so was told to avoid the golfball type.