Rescue victims, where to buy

Where do you buy rescue victims (balls) for Robocup Junior Rescue Line?

We have not decided on a specific vendor.

I usually suggest to Local Organization Committee like as below. They found and bought to prepare the world competition.
For example, if you search for “50mm stainless steel ball” at a mail-order company, you will get some results. Similarly, try searching with “the wooden ball 50 mm”.