Highlander Airsoft does the full treatment of the ICS M4 CXP M.A.R.S. SBR "Pro Series" in this hour long video review. This is an S-AEG as this is available in Germany. As to what its "Pro Series" designation, here are the enhancements made to it:

• Maple Leaf 6.02mm tuning barrel made of stainless steel
• Maple Leaf Diamond HopUp rubber (is installed in the right hardness depending on the desired energy)
• Maple Leaf Omega Tensioner
• ASCU Gen.5 (Mosfet, battery monitoring, cycle monitoring, active brake, electronic fuse)
• FPS Lightweight Piston with steel teeth
• FPS Advanced Pistonhead aus CNC Aluminium mit Double O-Ring und Kugellager
• FPS CNC Aluminium Cylinderhead mit O-Ring und angepasstem AOE
• ICS Aluminium Air Seal Nozzle mit O-Ring (20,92mm)
• Retro Arms CNC Flat Trigger"