This is the RC4wd 45T Rock Crawler Electric Motor.
FEATURES:

Equip or upgrade Any 1/10 rock crawlers for more
low end pull and more speed then a 55T
Preinstalled bullet connectors, no soldering required
YOU WILL RECEIVE:

45T Rock Crawler Electric Motor with bullet connectors
REQUIREMENTS:

Compatible speed control for rock crawler motors
SPECIFICATIONS:

Shaft diameter: 3.2mm (0.12")
Shaft length: 12.5mm (0.49")
Can diameter: 36mm (1.4")
Can length: 50.75 (2")
Weight: 164g (5.8oz)
Mounting Pattern: 25mm (0.98")
Wire length: 115mm (4.5")
Input Voltage: 4+ cells (12VDC) max