Completely CNC-machined from high-grade alloy, immensely strong and light, gold plated. RPM limit has been tested beyond 100,000 RPM. Dynamically balanced. 12 bladed fan design, super quiet and efficient. The fan has built-in safety, the rotor cannot escape the shroud, even if your motor shaft breaks. Virtually immune for foreign object damage, no more expensive replacement of carbon fiber rotors if you suck in a bug. The inlet lip is removeable, making it even more versatile. This version has a removeable tailcone, if you want to strap it to something like a Falcon 50 or 120. You can use anything from 6 to 12 cells, pick your KV accordingly. 12 pounds of thrust is easily attainable on 12 cells. These are in stock here in New York, ready for immediate shipment. These fans are the latest and greatest, stronger, lighter, and more efficient than anything else out there, for for less money, too.