We derive a substantial portion of our revenue from the sale of installed base products, which include replacement parts, various service and support offerings and upgrades to lithography tool manufacturers as well as directly to chipmakers.

We also provide ongoing support to our customers through contracts and service agreements. Under these agreements, we provide comprehensive support products to maintain the equipment within specifications. Certain contracts include the replacement of consumable and non-consumable parts.

Our OnPulse® contracts offer a comprehensive approach to enhancing light source productivity, offering our customers predictable light source running costs that scale directly with pulse utilization. We provide our OnPulse® contract customers on-site support from certified service engineers and continuous real-time light source monitoring. Replacement parts and support are covered under the OnPulse® contract, which facilitates cost savings for our customers as well as simplified order and asset management. We believe that our OnPulse® contracts offer our customers many compelling benefits, and this product has been well-received by our customers.

Our light sources incorporate certain modules and subassemblies that require replacement or refurbishment following extended operation, including, but not limited to, discharge chambers and certain optical components. We provide these and all other spare and replacement parts for our light sources to our customers. Customers not participating in a contract or service agreement pay for the parts and labor as the parts are replaced.

For additional information on our Installed Base Products, please refer to our Annual Report filed on Form 10-K.