Product review (4 stars): Ok product, but wish I had cleaned out drain catch first (probable cause of leaking)
Our Whirlpool Duet washer was constantly leaking, so I ordered this part on the assumption the bellow was leaking.  And actually, there were a couple of holes punched in the old bellow but I had previously sealed those up with 100% silicone and it appeared to still be holding tight.  Still, I went ahead and replaced the bellows.

It wasn't until after I had replaced bellow, that I noticed the drain clean-out access cover inside the lower panel.  I opened the drain catch and was surprised to learn it was completely filled with junk (shoestrings, pencils, pens, several dollars in change, lint, you-name-it).  It is very likely the leak was due to the drain pump not being able to completely empty the washer because of all the debris.  We had never cleaned this out in 8 years of heavy use.

So, before ordering a new bellows, I would highly recommend you clean out your drain catch first and see if that fixes your leak problem; just search "Whirlpool Duet drain catch" on YouTube should give you a nice demonstration of how to access, remove and clean out the drain catch.

Additional Note (11/24/2016):  Another possible cause of leaking, independent of the bellow, is having a sock get  down below bellow edge  and blocking drain holes; you can check by flexing the front bottom of the existing bellow towards the outside of washer, there you will see 3-4 small pencil-diameter drain holes; make sure these aren't blocked.