What is it?

You can use these card in industry standard ISA XT 8-bit or AT 16-bit slot which is backward compatible. Use card in conjunction with IBM PC XT 8-bit ISA Bus Raiser Extender Card to raise above motherboard for easier access and prototyping. Card has standard 62pin 2x31pin connectors with 45° chamfered edge for easy insertion.

Why did you make it?

I have originally designed this prototyping PCB card for few of my projects, but this turn out so well, that I have offered PCB's for minimum price for my fellow enthusiast such as yourself :)

What makes it special?

These boards look absolutely gorgeous in standard green solder mask if you going for that standard industrial look. I can advise you where to buy PCB rear mounting bracket, alternatively you can 3D print your own, files are all over my interwebs.