The Eureka F/G Micro Filtration Vacuum Cleaner Bags part# 52320A are the correct bags for your Sanitaire model S663 vacuum cleaner. The Eureka F/G Micro Filtration Vacuum Cleaner bags part# 52320A also fit Upright Models 600, 1400, 1900, 2000, 2100, and 5000 Series. 

Here is a link to our GoVacuum.com website so you can view and purchase the Eureka F/G Micro Filtration Vacuum Cleaner Bags part# 52320A: http://www.govacuum.com/genuine-eureka-f-g-disposable-dust-bag-52320c-6-3-pack.html

The Eureka Upright Belts Style RD, with the part #52100A, are the correct belts for the Sanitaire model S663 vacuum cleaner. The Eureka Upright Style RD part # 52100A also fit the Eureka Upright Models Series 600, 1400, 1900, 2000, 2100, 4000, 6400, and 5000 series except 5180, 5184 and 5188. 

Here is a link to our GoVacuum.com website so you can view and purchase the Eureka Upright Belts Style RD, with the part #52100A: http://www.govacuum.com/eureka-upright-belts-style-rd-eureka-part-52100a.html