Two Cossor "fat bottle" 53KU rectifiers made in High Wycombe, UK for sale.
These are the #3 rectifier in Debstep Girls' Massive Rectifier Review:
https://tinyurl.com/nu5daswuAnd have been my favorite rectifier in my UFO25s and non-Decware preamp. These tubes are used, but test strong and should provide many years of good listening in any Decware amp. They are among the stoutest 5V rectifiers ever made, and are indirectly heated meaning they have the same "soft start" feature as e.g. the GZ34. Note also there is a newer "skinny bottle" 53KU/GZ37 that is not these. Those are excellent tubes, but not in the same league as the original "fat bottle."
One is labeled "Cossor 53KU" the other "CV378" which is the UK military designation. Both have brown bases. These have been backup tubes, with changes to my system I find myself over-rectified.
$200 each, including paypal and USPS priority to CONUS. Buy both and save 10 bucks for combined shipping.
Please PM with questions.