I desined it from scratch with the Beat Aepli's plan. And I saw after printing it was already posted, so I put it as derivative. It's a realy easy boomerang, 10 throwing, 10 return this afternoon and I'm just a beginner. So I post it as proven design. Weight is 22g, 0.2mm layer Height 50% infile 5 perimeter shells And a lots of sanding to 100->150->180->320 to make it smooth.