A couple of the knobs on my grill broke and are no longer available. Aftermarket replacements cost $10 so I measured one of the existing knobs and designed this to match. It's about 2-1/2" in diameter at the base.Nothing fancy, use 3 perimeters so the fillets get printed nicely. I used 25% circle infill in KISSlicer. I've also printed them with 50% starting infill.