700W C-Band TWTA model XTRD-750C Manufactured by Xicom. Frequency 5.85 to 6.425 with a rated output of 650 watts at the flange.
Units new were purchased at $ 44k each. About 8 yrs old, 45k hours. Look like new. Tested and still make full rated power. We have four units on the shelf.
A very important point is that they have built in linearizers.