The Special Tech is a 3rd-tier class introduced in Valkyria Chronicles 2. They can be promoted from Tech Veterans as part of the Armored Tech Class Tree. Special techs are armed with smoke grenades which can block enemies' line of sight hence render interception fire useless.
Gallian Armored Techs
Special tech did not appear in Valkyria Chronicles.
Valkyria Chronicles 2
GRA Special Techs
The GRA have no known Special Techs