These Reverb Unit Reissues, made in the '90s, are now so well regarded that they are becoming collectable in their own right, particularly as the price of originals continues to rise.  And with good reason, they sound superb, so much more variation and subtlety that the built-in tanks just can't match.  This example is spotless, and it has a vintage 6K6 power tube instead of the stock supply.  I also comes with an "export" mains transformer so it runs on UK voltages.