in southern france 75 cm is mostly used by spearos looking for bottom fishes hiding between rocks or underneath stone slabs otherwise 90 cm is the official standard size this brand name more recent than other leading brands like Cressi Beuchat etc... makes very reliable spearfishing gear thanks 4 sharing : )
I have a 95 sniper and with the correct rubbers and enough spearfishing experience you could easilyget head shots on groups. Personally I have shoot many big groupers in their head and landed them in the boat no problem
The main difference is the grip design and style, but I am not sure about the trigger mechanism from the inside if there is a difference. Personally I like 3 because it is more comfortable for my hand
