This isn't clay, it's a professional modelling medium, once the model is made, silicone can be applied to the outside to make a mold and then you can cast as many models as you like in plaster or possibly concrete from that - maybe candles ?
It can be used again and again, it just needs to be gently heated to melt.
The container is about 16X20 cm (There's quite a big lump of it)