Do you let your children have cellphones?

At what age do you allow your child to have a cellphone?

We got our daughters cellphones - NOT smartphones - when they were in elementary school. The main reason was because our older daughter actually had a stalker and it was for her and her sister’s safety.

I didn’t allow them, but if they were in school now, I would diue to safety concerns- but with some sort of monitoring.

I do but monitor what they use it for.

How do you go about monitoring it?