A simple crank but fine for most bikes. Similar to their Defiant fixie & regular road cranks (already in a 144 and 110bcd) but with an even smaller 94BCD and which allows more useful 30/46 chainrings … with ramps & pins. Standard square taper. Boulder bikes are doing pre-order’s and suggest a 118mm jis BB, but on most older bikes I’m pretty sure a 116 should be OK (measure first).