It comes as standard with clear UV stabilised Perspex sides about 6″ high and the lid is slightly domed. This gives just over 8″ growing height which is about the same as most other propagators.
The problem with that height is that when tomatoes move into pots or over-wintering a tender fuschia, their isn’t enough head-room. Leaving the top off means heat is wasted, increasing your electricity bill and the danger of plants being damaged in a real cold snap in an unheated greenhouse.
The thing I love about the Vitopod is that you can buy it with double height sides and even buy an extra layer on top of that, giving enough head room to create a mini-greenhouse within your greenhouse and take really early plants like chilli peppers through to the warmer weather.
As every grower knows, the big problem with propagators is that they get humid with condensation dripping down the sides. This is a recipe for damping off and fungal disease. The sides and lids of the Vitopod come with large controllable vents so you can keep your plants warm but avoid the dangerous humidity.
My only criticism is the assembly instructions. I expect they’re good enough for most people but I’m useless with this sort of thing. I managed to put the sides together inside out, but it only took a few minutes to realise and fix my mistake.