I didn’t check it carefully upstairs

The definition of S-bag on the Philips website is

S-bag is the standard disposable dust bag that is widely available and easily recognizable by its logo. It is suitable for bag vacuum cleaners of Philips, Electrolux, AEG, Volta, and Tornado.

This s-bag is still a registered trademark. People want this dust bag Register as this name.

If you must use the full name, think of s as standard