how to have player breathe underwater

[ben246875]

so I'm trying to have a item that when you hold it, it lets you breath underwater.

i have 2 questions

1:how do i check when the player has it in their hand.

2:how do i make the breath underwater part

[MFMods]

1)  there is a player tick event. it fires 20x per second for each player. obviously you don't need that precision, skip 19/20 ticks or even 39/40. check items in inventory there. first check that it's a server player.

2) player has a field holding remaining air. just reset it to max. there are ways of preventing that field from being reduced but those are far more difficult that just setting the field to the max value.