picked one of these up a while ago and just forgot to make a thread about it.
There should be a triple shot version of this thing, but I have no idea if it will have the same switches as this version. Either way I wouldn't mind getting one of them to see. If I ever get a hold of the XT board that I half remember seeing with this mount for its switches I can dress it up fancy and hopefully use this over a standard converter.
The meme spacebar was mostly to see if it was possible, but also because the texture on the spacebar is rather aggressive, and angling it makes that less of an issue.
As you can see, the caps are a dead ringer for the other silver reed with proto-topre that I found a while ago as well as the black one in this thread but with some stuff in the middle instead of being a mostly empty slider. This is because this switch is less like proto-topre and more like a short version of the tall silver reed dome with slider switches.
The slider has three parts, a slider, a coil spring, and a pusher (maybe you could call it a click jacket, but it doesn't really click). The coil spring is compressed until the force upon the dome is enough for the dome to buckle and the pusher is then reset by the coil spring. It is similar to how SMK's integrated spring over dome switches work, but here it is way less clicky to the point that I wouldn't really call these clicky switches. There is a audible snap when the dome buckles and resets that is dependent on how fast you press the switch. Not a quiet switch but the sound feels more clacky than clicky.
To help with the height of the switch the domes are actually really short. This is not an issue because they are pretty snappy and the pre/post travel that the pusher provides makes up for the short dome travel. They are honestly a nice feeling switch, with a short snappy tactile event right before bottom out. The two buttons on the left use the same domes, but without the complicated slider they feel very different.
And for a peek under the space bar, not a lot going on here but it is always cool to see how the spacebar stab works. The space bar has 2 + shaped pegs on the bottom and the housing has a circular raised bit that can be used to hold a spring there to make the SB heavier. I don't remember if I added the spring myself (crappy mitsumi slider-over-pcb switches have external springs that are great for this sort of thing) or if it came with it stock, but it is very well stabilized spacebar at either rate. If I planned to use this more I would lube it to eliminate rattle, but as is it is plenty stable and smooth.
All in all, this connects this particular flavor of proto-topre to a switch that doesn't seem to be even remotely related to topre. apart from aesthetic similarities in slider shape. I'm not sure why brother and topre are shaped the way they are, but this switch mount is clearly shaped this way to accommodate the spring in the slider. They aren't compatible with topre and their design seems to be unrelated to topre as well, to the point that I don't think it would be accurate to call these proto-topre really. "Silver Reed short complicated dome over slider" just doesn't have the same ring to it. Still not sure what the triple shot green legends that are very similar to what brother used indicates anything or if looking like topre is just the keyboard equivalent of carcinisation. Good typing feel regardless.