It is as Bagman says - the thing doesn't really fit on modern bodies. But, what really grinds me is the thing is designed to funnel the plug into the jack so you have faster/easier cord plug-ins. But if you install the jack so that the funnelling feature works, you have to be careful what cords you use. Actually, it's not the cords - it's the plug design. If it has a squared-off shoulder, the plug doesn't want to go all the way in as it hits on the sloped sides of the Electrosocket. It'll feel like it's there, but then the plug falls out at inopportune times. Some plugs work, as their shoulders are rounded off, but who pays attention to that sort of thing?
The thing to do if you want to mitigate that is to install the jack so it protrudes out the center of the Electrosocket, but then you lose the funnelling feature.
I know I'm being petty; it's just a pet peeve of mine. It is an attractive mount. But, to me it fails in practice so it's unacceptable. I never want to fight with an instrument.