Two new AC/Delco pre-cat O2 sensors, still in the original sealed bag. Purchased direct from dealer but they won't take them back because they are electrical. After purchasing them it was determined I need to use the rear O2 sensors from a late model C5 with better heaters due to my headers.

GM P/N 25312197 O2B1S1
GM P/N 25312196 O2B2S1

Purchased 10/25/04 for ~$97 each. $100 for both and they're yours. That won't cover my cost on the correct sensors for my application, but it's less expensive than getting them new from the discount shops. You're welcome to the receipt as well if you want it.