[Vov]

Well, I can tell you some of the requirements which a spearfishing gun trigger should comply with...
1. It must be able to take 2,or 3 or 4 or 5 bands' load of up to 20 mm EACH...
2. In the 2-5 bands envelope, the trigger firing effort should not increase more than say from 1 to 2,5 kg...
3. That same trigger mech should be silent during firing.
4. It should withstand probably between 2000 and 3000 live firings for 5 years with no repair - just rinse in 'sweet' wat water after each hunt.
5. It should have a relatively short pull...
6. It should not change the effort of pulling regardless of the time in the armed position with the bands on...
7. Etc., ...