The butter maker works extremely well, it took only minutes for me to make my own butter. I read the hints from the Lakeland team, and these helped me a great deal. I think the trick is to make sure the double cream is very warm, these days we do not like the thought of dairy products being kept out of the fridge, and I think this has been the problem when the gadget has not worked. As regards to the seal, it works perfectly, no leakage, again as said on a previous review; it is removable, just make sure it is tucked under the threads on the lid. Great product!