Like any material, however, they are not completely impenetrable.
en.wikipedia.org Along the way, he is enhanced by a regenerative nanotechnology process, which gives him an impenetrable metal body.
en.wikipedia.org He depicts the difficulty of capturing, snaring, or taming him, his vast size, his impenetrable scales, his flashing eyes, his snorting, and his immense strength.
en.wikipedia.org Even today, the swamp is impenetrable in places; a research group gave up in 2003 because it lost its way so many times.
en.wikipedia.org Whereas dense, hard, impenetrable materials like metals reflect most.
en.wikipedia.org