FCW Swordfish Conversion Kit for MP5 Series AEG -Part
 
High Strength Full metal / Aluminum Construction
Provides a bridge for the entire rifle to prevent wobbling.
Kit includes all necessary hardware for top rail and front end conversion.
Works with MP5K and similar series Airsoft rifles, especially for Plastic Body Like TM, CA (Plastic Sportline), JInggong, ICS 
Maybe need modification on different brand MP5K