ZIPP 400's - Used

I have a pair of older ZIPP 400 tubulars for 650 cm that came with a bike I purchased used a couple of years ago. I just upgraded to a new bike and don’t need these wheels anymore. I’m curious as to what they might be worth, as I have no clue. I’m guessing they are 1998-1999. They are in excellent condition with very low miles on them. Any ideas as to what they might be worth? Thanks.

Just for reference, I sold my 440’s for ~350 on ebay a while back. They were 700s, airborne ti skewers and no tires. Put them on ebay if you really want to know–the market will dictate the price. eddie.