Not sure, didn't weigh it. Dragging it up and down the stairs with all (empty!) panniers and trunk bag, it was quite a bit heavier than I was used to!
Also yeah, I completely agree with the Topeak Trunk Bag. By far the best purchase I've ever made for the bike. When I was commuting to work it was absolutely perfect. Stored 2 tubes and my entire repair/safety kit, cable lock, lunch, and U-lock. And if I needed to bring extra clothes or equipment to or from work I could just unfold the panniers. I can do pretty much any utility shopping besides grocery shopping with it.