I can't believe it that I had forgotten that there are rubber balls too for playing cricket [COMPACTIDEA]

Guess it has been quite many years since I played cricket, or perhaps it has been many years since I was a small child. Maybe both. It was a bit of a strong surprise for me a few days ago when I saw a rubber ball - most likely after 10-15 years - and realized that there are rubber balls too for playing cricket. How could I forget this? I, who as a kid had collected so many abandoned/lost balls of all sorts from playgrounds, roads and elsewhere? I had forgotten the rubber ball?

Anyway. When I was small, I remember there were 4 types of cricket balls:

1. "Cosco" ball. We used to call it Cosco, but it was really tennis ball. The softest.
2. Rubber ball. Heavier and harder than Cosco ball, but still very gentle.
3. Leather ball [red leather or white leather]. Heavy and very hard too.
4. "Corak" ball. Sort of a white stone. Heavy and hard like a stone. Quite dangerous.