Modern toilet system has two flush buttons, Smaller and Bigger size. This is basically to achieve water sustainability. Let's see how it achieve.
This type called as Duel Flush system. Two type button attached to two level of water dis-engage valves. This vales operate different height of ware levels.
Simply if you press Small button it Disengage small water content (3 to 4.5 Liter water)
If you press Big Button it Disengage Large water quantity (6 to 9 Liter Water)
So please use this buttons as per your requirements and help to save world with simple button click.