Description: -The Precision CNC Main Gear is designed to improve the performance over stock main gear. The main purpose of this upgrade is to provide true, round and un-wobbled main gear. This material will make the gear stronger and therefore it is not easy to wobble. It is produced by CNC machines so it is absolutely true and round. -The main gear is to replace CNC main gear of MH-B4102 It is NOT to replace stock main gear. Includes: -Precision CNC Main Gear Requires: -Assembly Weight: 8.8 grams Usage: -E-flite Blade 400 helicopters Instruction: -Instruction included in the package Features: Precision 100% CNC machined delrin for TRUE and ROUND main gear. Unique and stylish