I bought this because I was inspired by the "Bento" lunch boxes shown on Pinterest.These Ziplock containers seem to be fairly water tight. At least my cottage cheese didn't soak into my sandwich and fruit. It didn't warp when washed top rack of dishwasher.My biggest disappointment is they are too large to set flat in my "31" brand lunch box. They are also too large even for my husband's "6 pack" style lunch pail.Still I'll use them and enjoy the cutesy factor...anything to brighten up brown bag lunches.