If you're a serious home mechanic . if you buy frames and put parts on them or do your own maintenance in your own home bike stand . you'll find this to be a strictly unnecessary but super nice tool to have.
A seat post does the same thing . but if you work on bikes a lot . you know that sometimes for any number of reasons . the seat post is not up for grabs. Lights or saddlebag or some kind of rack or support on it . not enough of post exposed . and if the bike goes in and out of the stand frequently . there ought to be a faster . smoother way to put it on and take it off. This thing . which we're now calling a Frame Quill . was developed just north of Mexico . at Joe Bell's painting place . because they're good for painting bikes . too. Every Rivendell frame that's come though here since has been held in place by one.
The frame quills we have here are deluxe versions of those. They're made Jim Stein . whose shop in Arizona is also north of Mexico. We sent him a sample and said . "Jim . make it better ." and he did. We thought we'd have twenty of them made but we've had at least two hundred and fifty . because they kept selling out. get any more of them.
Two sizes: Skinny . for frames with that take seat posts anywhere from 26.8mm to 28.9mm <--there's no such thing as that size . but if somebody makes one and you have one . these'll fi); and Fat . for bikes that take seat posts 29.8mm to probably 32mm.
Grease the threads at the bottom of the bolt . and don't overcrank it. If you regularly snap shoe laces and can't drink a beer out of a can without crushing the can . stay away. Othewise . don't sweat it . just be your reasonable self.
Selling pro tools for home use is a lousy plan to make money . but we like to bring you super neat stuff when it comes up . and this is one of those things. This is the second-to-last time we'll get these. Onward . etc.