the window fitting can be removed in seconds with no damage to anything. Had to test for leaks and sealed a few with some cardboard, the window frame nor the cover I made is 100% flush, but it's light proof now. All that's seen from the outside is a 3/4 open verticals in front of a faux blind. the window itself is open 1/4 and there is lots of fresh breeze here. The light kit STILL hasn't arrived ,I'm really expecting it tomorrow. So hopefully tomorrow I can finish the little room. I want to get nine 10 litre hempy buckets ready, these new seeds will never be transplanted, they can go straight into a 10 litre bucket