When i started riding a bit of DH & jumps i did a lot of looking & reading online for the coolest ( ventilation not social status cooool ) full face helmet, i wanted full face protection but max ventilation for trail riding / uphills etc.
I was going to get a MET parachute , but expensive & more XC than AM / DH, plus expensive & hard to find as they stopped making them.
looked at the casco viper, the old giro switchblade but couldn't find one, parachute, specialized deviant but couldn't find one.
so what i ended up getting was the Pryme AL, it has heaps of vents & is more AM style than full DH, i've since got a 661 Comp shifted for full DH riding & have now modified the Pryme AL as purely my AM helmet to have even more cooling by removing the jaw / cheek padding, rear of neck & around ears.
where the padding is left up top is similar to a skate ( dome) helmet amount of protection for my head, but obviously has full face coverage plastics.
i use it when riding AM & uphills is slightly warmer than a XC open face but still gets heaps of air flow after my mods & once moving along the flat or downhill the airflow is awesome !! some might say overkill for AM riding but i like it & have seen people with face raper injurys from cruisy AM riding & i ride it like a mini DH bike when decending.
anyway here's some pics.
outside of helmet
inside before mod
inside after mod