The California Office of Tax Appeals (OTA) held that a taxpayer is liable for use tax on parts used to repair equipment in California for out-of-state customers. The taxpayer is a distributor, retailer and repairer of endoscopes and other medical devices. The taxpayer offered optional lump-sum maintenance contracts with the sale of its products and provided the materials, parts and labor for warranty repairs free of charge.
Source: salestaxinstitute.com