Lens Effects - How to set Material ID

unhandled

#1

I’m working in v3, trying to create a realistic glow from an LED. I’m using Lens Effects Glow and Bloom but I can’t work out how to assign a material ID so the effect only works on the emissive LED material.

The Lens Effects dialogue is asking for a material ID numeric value, whereas the only way of assigning an ID I can find in the material editor is using a colour.

I’m clearly overlooking something here - please can somebody explain how to limit the Lens Effects to a specific material. Thanks for any help offered.