### Clue: Smart card contains expensive piece (7)
### Answer: SIDEARM 
 ### Explanation: Definition: piece
 SIM(abbrev. for "subscriber identity module", the smart card/microchip used in smartphones/mobile phones with many IT capabilities) **containing**(contains) DEAR(expensive/at high cost).
Defn: …, slang for a firearm/a portable gun, in this case one worn at a person's side.