How to take the cap off SDLaser 301

I have the SDLaser 50mW focusable, DX sku 26532. I seen other people take the focusing cap off. I would like to do so too, to install an IR filter. I don't know how to take it off, I don't want to break anything. Does anyone know, how to do it properly? :thanks:

You have to rotate it, like when you focus it to burn. When you reach the limit, you have to apply a little more strength and you'll be able to remove it. I did it.

Thanks a lot, it worked. Now off to put the filter in!

edit: For some reason, after removing the strange glue debris that were there, it focuses to infinity much better and now has a diviergence of 1.05 mRad. Didn't meaure it before, but it is surely a lot less. Thanks again!

It's the best beginner's laser. It was my first laser and I don't regret.
It's pen price, but in a very good solid host and overspec module.