- This is a set of 4 Raytheon 12AU7s with long (17mm) Black plates
- See all the photos for internal construction details
- They all tested good on a Sencore TC-154 emissions type tester
- They were also tested for Grid leaks and shorts, but had neither
- One tube is dated 57-09 (ninth week of 1957)
- Two tubes are dated 57-27 (twenty seventh week of 1957)
- One tube is dated 58-17 (seventeenth week of 1958)
- All of the tubes have 280, the EIA code for Raytheon
- FREE DOMESTIC SHIPPING!