Where can i find one?

I bought one from ebay, it was a babies nursery one and only cost a couple of pounds including delivery.

I have just been looking on ebay at some.

Thank you.

Lois

Hiya, I just use one from a garden center, I stick it just above whelping box with blutack. hopr this helps

I don't use one.  I leave the house central heating on 70 degrees (for me) and I just see that the bitch and pups are content. :)  But I do have a closed in Snowsilk whelping box.  I wouldn't be happy with the open boxes that most seem to use.

I looked at the snowsilk whelping boxes and they are very nice, i decided to buy a likaboard box and a newborn one, not sure which i am using yet! We have about two weeks left and she is not looking very big at all so she will probably use the smaller disposable newborn one. I am going to set things up in our room early next week.

If the Newborn one is the cardboard one with a lid, then that would be my choice. :)
I've also seen friends fix puppy panels around an open whelping box and throw a blanket over the top for the first 2 weeks until the pups develop their shivering reflex.  Cold kills more puppies than anything else but overheating distresses the bitch.

Yes thats right, it has a lid.

Thank you very much for your advice! :-D