I've been struggling to find the "perfect" ER32 collet organizer (cut one out of acrylic, modified a fishing tackle box), until now. I have a set of 11 fractional collets (plus a 20mm), and I just ordered a 19-piece metric set. The 11-piece now lives in your collet holder. For the metric set I downloaded the STL file and opened it in TinkerCAD, divided it into 3 sections, and repeated the center section 2 more times. Once I combined all the sections back together, I now have a tray for the 19 plus 1 metric collet set. Thank you for your most excellent design, it was just what I was looking for. If you have no objection, I can upload the 20 collet 3MF file as a remix, your call. I downloaded the STL file and printed it at 15% so it's not showing up on my Ratings tab for me to rate. It's definitely 5 stars in my book!