I’m not sure where or when my Dad got this demand valve but he’s had it as long as I can remember (I’m 46) but I have never seen it being used (and used to dive regularly with my Dad).

Overall the outer condition of the demand valve is good but I haven’t opened it up to check the internal parts. As can be seen in the photos the original twin hose is included but it is badly perished.

Please get in touch if you have any questions or need more photos, information, etc.