Product review (5 stars): Duet Sport Washer Fit
The belt is the exact belt that fits my Whirlpool Duet Sport Front Loading Washer with stainless steel basket.
My model # is  WFW8300SW03  Type 831

It will almost seem like the belt is too short, but the belt will stretch enough to rotate it on there, but you have to give it some muscle, and put it on correctly per whether you are left, or right handed.
In my case with my machine I had to lift up and remove the two support brackets that span across the upper and lower part of the machine, you have to take the back off first to get these listed and removed.
Shipping was fast, and it allowed me to fix my washer in about 15-20 minutes.