Need vacuum rubber seal for my micro seiki platter

I need help finding rubber gasget for my micro sx-8000 platter. The rubber seal (gasget) is torn and need replacement if anyone have extra parts that want to sell or give some pointers to where i can find one that would be greatly appreciated. Thx
If you can measure it, you can propably find a replacement in the Grainger Catalog
What is the diameter from the outer edges of the rubber seal?