Put this in a small greenhouse with light weight roof panels. Works wonderfully.

I purchased the heavy duty Bayliss Autovent MK7 with triple springs to replace a light duty Autovent in the roof of my greenhouse. The push rod became bent during a severe wind storm. The triple spring MK7 was a perfect fit 10-minute replacement. I highly recommend the Bayliss Autovent. Except for the one wind-damaged vent, mine have been trouble free for three years.

I like this autovent very much, it's well built and works well. The one limitation is that I've attached it to a cold frame, need to get into the cold frame to water, and sometimes have to open the top far enough that the piston comes out of the end. A quick release of some sort would be helpful.

Installed on a Sunshine Gardenhouse. Needed to move the roof vent strut up an inch so this could screw into the flat rather than into the 1/4" width. Measure several times and predrill your holes.

You can remove the 2 outer springs to make installation easier as you check the motion. It feels a bit wobbly as you install, but the action is smooth.

 

Easy to install and I went with the one that had springs because I live in a windy area.