http://www.testequipmentconnection.com/specs/PHI%20PM6666%20SPECS.PDF I forgot 2 things: a) it's also a voltmeter :) Somewhat limited but it's a "free" function" b) there is a lower cost PM6669 version. I have seen these go for < $250 on eBay. I think I paid ~ $2200 for mine new with the high-stability oscillator. This was 10 years ago. Paul S.