The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.

The knobs are designed to last a long time with proper care, but like any glass surface, they can be scratched. You should not hang metal coat hangers on them or scrape them with other metal objects.