The three models from WE which carry the Katana System and their cylinders are now in stock at RSOV.com... "KATANA System is a new AEG system design by WE Tech, a Quick change cylinder unit design, easier to repair and more flexible on swapping power. Original pack comes with red cylinder unit, giving 1.2 Joule power (with0.2g bb),good enough to cover all mid-range outdoor field and indoor game. WE KATANA system also have standalone cylinder unit with various power for optional performance parts.

• 0.8 Joule cylinder unit in blue color
• 1.7 Joule cylinder unit in grey color

Furthermore. KATANA system gives us a great function on release the spring by switching the selector to safety, it’s a good function to keep your gun a longer live time, and keeps the spring power.

WE KATANA system is compatible with Tokyo Marui M4 AEG Magazines, even low cap / mid cap / high cap. The chamber unit also compatible with ordinary M4 AEG system."