Since you are still on a prototype phasis, I provide my feedback from the usage of D620 so you can get some ideas for the next release.
The torch is great and the price is good, some suggestions:
1) the cannister is too short, so in tech dives you cannot use it to hold the primary reg hose and you need to workaround with something like this
Apeks Long Hose Retainer
2 ) The beam is too wide. I see you have a laser pointer like the one in
D570-GL. For tech diving it would be amazing to have it embedded in the primary torch as one of the main function of torches is for signal
3) The hose is a bit too tight compared to halcyon, for this reason it floats and is too flexible and tends to move around and create circles. I will probabily fix some fishing weight to work aroung the floating problem
4 ) Battery duration is not huge, it would be great to have a replacement with a larger on ( like the one in D630 with 8x18650). That would probabily fix also problem number 1
Last, I have just bought a d620, do you provide any replacement policy for those who want to buy the new model ?
Thanks!