The 540-M4 Driver Edition is technically identical to the standard 540-M4, but is instead equipped with the ASC27447 rotor, giving the motor an improved throttle feel and greater consistency.Required to Complete:Soldering of motor leads of desired length and thickness.Features:CNC-machined lightweight canAluminum end capLow-resistance, silver plated solder tabsOptimized air coolingDual precision ball bearingsBalanced rotorPerformance specific magnetAdjustable timingCompletely rebuildableCompetition provenROAR, EFRA, BRCA, and IFMAR approvedSpecifications:Cells: 1-2s LiPoDiameter (mm): 35.9Length (mm): 50.3Shaft Diameter (mm): 3.15Weight (g): 160-170Bearings: 1/8 x 3/8 x 5/32 (x1), 1/8 x 5/16 x 9/64 (x1)