Another hunting light review this month. 
SPERAS kindly provided the TH4 for review.
The head can be twisted to zoom in and out. The action is smooth. It came well lubricated.
A rotary switch on the head has G, W, R and IR markings for selecting the Green, White, Red or Infrared light. The switch is well lubricated and it gives a satisfying click when it is rotated and clicks into place for the next LED.
A rotary switch on the tail can be clicked to turn the light on and off and it can be rotated to adjust the brightness. It gives a satisfying click when pressed and it turns smoothly. You could press and hold the button for momentary on.
The lens looks a bit like a fresnel lens. This may help with focusing the beam.
Here is my full review: