The Spektrum RC Firma Sensored 540 Brushless Crawler Motor is a great choice for 1/10 scale crawlers, rock racers, and trailers running on 2S – 3S LiPo power. This motor features a low cog 4-pole 8-magnet rotor design, a CNC machined aluminum housing, insulated high purity copper windings, high-quality alloy steel 3.175mm (1/8") output shaft, and precision bearings for high durability and smooth rotation. Preinstalled with 4mm gold plated bullet connectors for easy installation. The Spektrum FIRMA 60A Sensored Brushless Smart Crawler ESC is required to complete this package.
 
Features:
Excellent upgrade for 540 brushed motors with the same diameter and mounting pattern (vehicle must accept pinions with a 1/8" mm bore)
Perfect for low speed, high torque applications such as competition crawlers
High-quality 4-pole sintered rotor
Polarity protection - magnetic encoder inside the motor guarantees consistency between three phases’ signals and always outputs precise signals indicated by rotor position. When installing simply match wire color to esc connectors
4mm gold plated bullet connectors
Waterproof sensor wire with locking plug and gasket
High-quality construction with precision ball bearings and hardened steel 1/8" shaft
Specifications:
Type: Crawler 
Motor Size:1/10
Application: 1/10 scale crawlers, rock racers, and trailers running on 2S-3S LiPo power
Connector Type: 4mm Bullet
Product Length: 2.27" (58mm)
Recommended Speed Control: Spektrum Firma 60A Sensored Brushless Smart Crawler ESC
Reverse: Yes
Water-Resistant: Yes
Forward: Yes
Maximum Continuous Current: 38A
Bushing Or Bearing: Bearing
Number of Poles: 4
Motor Type: Brushless - Sensored
RPM/Volt (Kv): 2100Kv
Input Voltage: 7.4 - 11.1V
Outer Diameter: 1.42" (36mm)
Shaft Diameter: 0.125" (3mm)
Overall Length: 2.27" (58mm)