It’s a pretty durable 6 mil plastic which does have the words “inside” written across the sheet to indicate which side should face down. I didn’t see the writing as an issue once it was put up.I have an existing rectangular area garden with a fence connecting to the side of the house so using a more traditional raised metal arch as described in the listing is far from what I ended up with. Mine is more like a tent, with several raised areas.It’s thin enough to droop where there are no inside supports but can be made fairly taught at the ends. Doing it the way that I did, I realized there’s no way it was going to be tight across the rectangular area, not with a piece that is of this size.As to the temperature aspects, if its sealed well about the perimeter it will likely (my area isn’t air tight) hold the temperature several degrees higher long after the sun goes down. During the day expect temperatures to be a good 10 degrees or more warmer inside than outside.Interesting to note – all of the flying bugs that I never notice otherwise in the garden have an affinity for crawling on the inside surface, and usually collecting at the highest points where it has been raised up. It’s probably something to do with the way the light refracts through the plastic. It is clearer than standard 6 mil hardware plastic as you can make out things looking through it.Something I thought about ahead of time where I’m using 2×3’s to prop it up inside, was to sand down the ends and corners of the wood. The plastic will move with the wind enough to cause friction across these contact points and ultimately begin tearing holes in it. I had some scrap material that wasn’t sanded.For my scenario it may give a complete season and then probably get discarded. If the plants get enough sunlight and are protected overall from frost then I may go the more expensive route next year, and install the rigid greenhouse sheets instead.