Shopping from Amazon?

I'm trying to get some more adjustable KF94 or KN95 masks for my family (those are the only ones they feel comfortable wearing and I don't feel like trying to convince them to wear N95s or more again; I'm glad they wear masks at all). Is it safe to shop from Amazon? I saw some adjustable KF94s that were on the cheaper side (I don't have a lot of money to spend).

Also, where do you get those silicone adjusters (if I said that right lol).

Any suggestions and tips are welcome. 😁