This is required on the majority of Garrys Mod 10 servers and is a mod with more models for the game. If you don't have this mod and you join a server with phx on it you won't be able see a lot of the things people make and they will show up as error signs which is annoying when your trying to see what people are constructing. GameArena servers also use this mod.

What if I already have your GMOD10 PHX 3 - V4 Conversion Installed?:
Delete PHX from the addons folder, then Install PHX FINAL

When I upgraded on older versions, the old spawnmenu stayed, and I got a new one, why is that?:
Yeah, Seems Addons copy the spawn menu into your garrysmod folder, when you upgrade to this one, it'll fix the errors old copys left

What does FINAL Contain that v4 Didnt have?:
-30 Props I missed (Sweet Jesus..), Completing the PHX Pack.
-More organised menus.
-Added Gears to Wheel Tool
-Added RT Screen to Button Tool
-EVERYTHING from EVERY PHX Pack, EVER.