This thread reminded me that I had bought one of those a few months ago for my Wista 45, which came to me with a crinkled bellows. This afternoon I took the old one off (easily with a palate knife and alcohol) and fitted the new one. The new one is marginally smaller on the large end, but will work fine. Installation is fairly easy with contact cement.
Like Paul, I am happy with the price and material quality. I can recommend this product.
I also bought one (a bit more costly!) for my Deardorff Special, but have not installed it yet.