Want your GHK M4's performance increased to the higher level? With precise calculation, revision and testing, piston internal with T-N.T. specially modified High Flow Piston Kit which can be simply installed, it will significantly the airflow efficiency.
Want your GHK M4's performance increased to the higher level? With precise calculation, revision and testing, piston internal with T-N.T. specially modified High Flow Piston Kit which can be simply installed, it will significantly the airflow efficiency.