Towards the beginning of Avengers: Infinity War, Peter Parker is on a school bus. When Peter notices alien ship in the sky, he immediately asks the kid in front of him to create a distraction. The kid makes a distraction.
Then Peter places something (I think a mechanical device) on his wrist and goes outside of the bus. What is that device?
When did Spider-Man start using these devices for web-slinging? I thought Spider-Man can shoot webs from his hand biologically. Isn't it?