An absolute MUST for safe, satisfying flights. Why take chances?... An improperly balanced model-at best-won't be able to fulfill its true performance potential. At worst, it could crash and be destroyed. Why take the risk? Great Planes' inexpensive, easy-to-use CG Machine is the only tool that finds the exact balance without guesswork...and it can be used with virtually ANY fixed-wing aircraft. Simplifies the essential final steps of any plane's assembly: locating its recommended center of gravity and correcting the balance. CG Machine's accuracy improves a trainer's stability and predictability...sharpens a sport model's aerobatics...and boosts a racing model's speed. Works with all types of fixed-wing aircraft up to 40 pounds-kits, ARFs, high-wings, low-wings, with or without struts, regardless of size or wingspan. Wide, injection-molded base improves stability and can be slid apart or together to accommodate all fuselage widths. "Hands-off" operation eliminates fingertip balancing's huge potential for error. No additional tools or supplies needed!