Trigun What is the silver shooter (Vash's silver hand gun)

Besides the obvious answer, does the silver shooter sever as part of the angel arm or is it just a trigger for it? Also who actually gave Vash his handgun? Some web pages say Knives did. However, if that is true then it would be logical that knives had the alternate model, the black shooter (hand gun) and vash had the silver shooter, however since i got another dvd (I am rather slow to complete my trigun collection) ep 17 or 18 showed vash with the silver and black hand guns facing off against knives, then he got his left arm shot off. So did Knives create the handguns or did the colonist who also made his replacement left arm create them?

 

The 'silver shooter' was made and given to Vash by Knives, who also made the 'black shooter'. You need to watch the episodes where they talk about that, (last disc, if I remember properly) I don't like giving spoilers. As for how Vash had both guns, it's in the same segments. The colonist just created the arms for Vash.
Get the DVDs!

-UK