Emisar D4s

Looking for some help/information regarding my Emisar D4s. Not sure what happened but the spring on the head of the flashlight is missing and the light obviously doesn’t work. Where would I buy a new spring and is the proper way to attach the spring to solder it? Is this possible to do without damaging the head of the flashlight because of the heat required?
Thanks for any help.

I am sure Emisar has parts available. Great company.

Yes, soldering is the correct way of attaching it.
Heat shouldn’t be a problem.
Ask Hank from intl outdoor about a replacement.