I guess the real Imperial Voigtlander's mentioned in the Vade Mecum are even bigger, but this has always been the crown jewel of my humble collection. It is massive.
Years ago I did this portrait of my brother-in-law with the Eastman 8A 11X14 and it remains my best effort to this day. I used this lens. About 44 inches of bellows.
It's early. I would date it about 1872, but the 16XXX's we're guessing. It's also in superb condition.
I always said it was a 21" but measuring it to the slot, it's more like 19 1/2" or so. Covers the 11X14 very well. I put things in for size references. You'll need at least an 8X8 lensboard. 9X9 or 10X10 like the big 8A has are perfect for this.
My price is fair at $3150.00 and $50 for shipping in USA. Don't wait for the next perfect one, it may never come!