There are lots of fancy thru axle adapters out there for wheel building. Ain’t none of them as easy to use or as inexpensive as these here. They’re made by Unior, and come in 12mm or 15mm thru axle adapters. Not for riding, only for truin’ a Schmidt 15mm hub wheel in your VAR Truing Stand.
You just slip them in the axle, then plunk the wheel down on the truing stand. Also works with lesser truing stands.