CerMark Ultra is the best for black marks on glass and we have stopped selling CerMark coating 6044 except by special order. CerMark 6098 is used to make white mark on glass and ceramic items. 6098 is only supplied in liquid form and must be applied by spraying on to the item. These coatings can be used with CO2 or fiber lasers if they go to 200 kHz. or higher frequency.