Ahem, er, sorry, back to the mattresses.......! (I shan't comment on my respectability levels cos I don't like to lie to the police.) ANY-way, iHs, I don't know about the toppers but the mattress I bought has a full, zipped cover, which is removable and washable, it's breathable and the only time I get too hot is when I'm going hypo in bed. The thing about the memory foam technology is that it uses body heat to kind of 'sense' where the body is and that part of the mattress shrinks to fit under you, which is the good thing about them because you feel 'supported' (for obvious reasons therefore it says it's not recommended to use an electric blanket). I removed the whole mattress cover once to wash it, and I have to say doing it myself was like wrestling a lion (they really DO fit snugly) and I had a hypo taking it off and another one putting it back on again!! But, it's fab, you just stick it in the washing machine, it's a sure way to keep it clean and no need to worry about sweat! Plus you can just buy another one of the covers if things go really badly wrong or take it to a professional cleaner but I've had mine 5yrs with none of that bother. Over the summer I had my flat refurbished and part of that work was to get my bedroom floor made level so that I know have a really fantastic 'sleeping experience' on a flat floor with a fab mattress! Btw I think I chose to have the 15cm memory foam bit at the top rather than the thinner one, I thought in for a penny in for a pound and they were so cheap from this site that I didn't feel the need to go as cheap as possible.