Replacement part if the original protective plate is worn out. For maximum safety and comfort, make it a habit to check your equipment regularly. Replace worn or damaged parts. Clean regularly and replace if it cracks or becomes too scratched. The Speedglas 9100 standard external protection plate is designed to protect the welding cassette from sparks and metal splashes. If you do not use it and the glass of the automatic welding cassette is damaged, you will not be able to claim under warranty.