Need Belt Kit For Panasonic FW-20 & Sharp GF-8989II

Hi everyone-I'm looking for a belt kit for a Panasonic FW-20 double cassette deck stereo & a Sharp GF-8989II.
How & where do I find these belts for these particluar stereos or do I have to measure??
Now the Pana won't be hard to measure those but the Sharp-I won't be taking it all apart until I do the job.
Is there belt kits for these particular models?
I appreciate any help on this as I need to buy these belts soon!
I wouldn't mind buying an extra assorted sizes pack for future projects to.
Thanks-GB.

gb most of the time measureing would be the best way after you have it go to studioelectronics.com and you will find a whole selection of belts and other stuff you might find interesting this is where i have been buying my belts from

Thanks Ramon-I have the old belts out of the FW-20 and I'll need those and probably an assortment pack to.
I just don't know the sizes needed for ther 8989 because i don't have it apart and won't until i actually do the job.
So an assortment pack and any help if anyone knows would help!
Thanks ramon-I'll check it out.
I need to do this soon and hopefully the belts aren't to expensive.
Have a great weekend-GB.