Sturdy hemispheres and ellipses cast from precision molds in clear acrylic.
These domes come from precision molds, and are cast under controlled temperature and pressure for many hours. The larger domes (larger than 1 1/2" diameter) have a small bit of plastic at the top of the hemisphere where the acrylic is injected into the mold; you will want to remove with a flush cutter or small saw. Sand it with 400 and finer sandpapers. The smaller domes have a small indent at the top.
If you want a clean, crystal clear finish you will need Novus scratch removers and plastic polish. If you have heavy scratches, start with Novus 3 Heavy Scratch Remover and a clean lint free rag. Novus 2 will remove fine scratches, and finish with Novus 1 Plastic Polish.