This Precision Shaft Collar is designed with 2.5mm lowest profile, lightest weight and maximum strength with dual set screws to hold tight onto main shaft. Weight: 0.10 grams Usage: Hornet FP, CP, Hornet II, Piccolo, Humming Bird, GWS Drangonfly Features: High precision CNC machined aluminum, 3.00mm bore with -0.01mm tolerance for maximum tightness Using 2 set of screws for maximum strength, tightness, and true-balance during operation 0.2mm step-up design to ensure non-fiction contact to bearing Lowest profile 2.5mm design to give swashplate more travelling pitch on Collective Pitch and Flybarless helicopter