This is a cement stone mold for aquarium. Mold can be 3d printed. It has hole in one of the spike, so you can insert cement. You can scale it and make the size as you want. No limit in size. Approximate dimension of the mold is 70mm X 65mm. I designed it for my aquarium.

Custom size and design possible, you have to contact with me for more details.

Thanks,Mahbub