These jackets are excellent quality.
I keep my fermzilla fermenters in.
my shed where the temperature can get pretty cold at night. I use fermenter heat belts to keep the beer at the proper temperature.
The insulation jackets make this a lot easier to do, they contain the heat from the belt regulating the temperature so I don't have to set the temperature so high.
They also hold the natural heat created from the fermentation.
Come summer I am going to pack the insulation jackets with bags of ice I will let you know how that works out.