For making it, we needed bicycle tube rubber, a 'Y' and a leather piece. We used to have old rubber tubes or we got one from the nearby Shivaram's Cycle Shop. The leather I have used to hold the 'bullet-stone' was the tongue from a discarded shoe that belonged to my grandfather. The 'Y' is from our Guava tree branch. Guava wood is strong. Hence it was the chosen material by us as there were many such trees in people's yards. We used to make playthings from the wood for Gulli Danda we played on the street!
Just a mock action of loading and firing from the slingshot was enough for the monkeys to run for shelter. They were so afraid of this! They knew the missiles came too fast from this for their quick reflexes which they could not avoid. If we threw stones at them, they would watch and follow their trajectory and continue to sit there on the parapet or tree branch. But just the sight of a slingshot would make them run away.
This weapon is lying idle now as monkeys have stopped coming to the premise since a few years, perhaps due to increase in traffic or availability of food for them in other places. But in the other locality where we lived till 14 years ago, they continue to be a menace.