just in case

US /dʒʌst ɪn keɪs/
UK /dʒʌst ɪn keɪs/
"just in case" picture
1.

por si acaso, por si las moscas

as a precaution; to be prepared for a possible event or situation

:
Take an umbrella, just in case it rains.
Lleva un paraguas, por si acaso llueve.
I brought extra snacks, just in case we get hungry.
Traje bocadillos extra, por si acaso nos da hambre.