the 404 silverato heel is as old as me, a proven at snow ski binding the swiss designed and used in ww2 that set the standard back ???
the 505 is the new version.
I used them 26 yrs ago AT skiing Back country in the nw.
if you set the system up correctly, it works great. I have never had a prerelease, and the 4 skiers I know have never had a prerelease either. and we have all crashed and released when needed
I have the skier put the boot on click into the binding with the fin hanging off the dock (set on 4 to start with for a skier 140lbs or more, )then I have them pull up on the heel like they were doing a OTF, was the release to easy? to hard? then adjust up or down until you get the relaesae were you want it.
also make sure when the boot is clicked in the system you can not pull the heel level off the back block, the boot should be hard to click into the system. I have seen many system ordered with boots that were to lose, ( you could pull the heel level back off the block ) simple fix just move the heel one hole forward. there should be resistance when pulling up the level the click in the boot.
Being a snow skier this binding makes the most sence.
Deano