Just like the weight of the victims of the blue rescue kit does not have a weight specified (so it is up to the LOC).
However, similar to the victims, they should be of lightweight material (e.g.: using wooden balls/blocks as opposed to solid metallic material). For the rescue kit, an idea is to use blue lego blocks for testing.
I'm afraid I don't have any real images of the rescue kit, but it should literary be a cube painted/coloured blue.