I use this in conjunction with my ACF 16inch greenhouse fan and it is really useful when you can slow the amount of air coming into the greenhouse especially when you don't want too much cold air blasting your plants in the greenhouse.

Fast shipping, great price.

Easy installation, common sense wiring schematic. Once set up, need

a very small screwdriver to set the speed adjustment to your needs.

Don't have this connected yet, but the watertight box is well built and compact.