The brush is ideal for coarse dust from the lens to remove as well as the viewfinder.
But I particularly like the cleaning sponge. Fingerprints on the lens can be removed easily by circles movements. Even small water spots (in the jungle hardly avoidable) are easily removable.
Due to the many years of use, unfortunately, no longer hold the cap. Even the cleaning sponge is flattened and begins to dissolve slowly. So I'm going to buy soon after 6 years a new.
Conclusion: For me, an indispensable tool in photography