Here is a little information for you
http://www.onlycubcadets.net/forum/s...ad.php?t=12992
You are looking for a QA 36a or a QA42a for your 129.
If you do find one for sale, try to get ALL the parts that go with it. Piecing one together will get expensive.
Look in the tech section and download an operators manual so you have an idea of what all you should be getting with it.
Yes, they use their own mounting system and belt.