Printed fast and seems resilient to me shoving sharpies in them. I only had 6x2mm magnets and was too lazy to modify the file itself so instead I had some of these magnet holders on hand. they were the perfect size to shove into the holes and then add my 6x2mm magnets only sticking out a tiny bit but they still work great. Link to magnet holders from my second picture. https://makerworld.com/models/1189329

Printed in Bambu ABS. Fit together perfectly and is exactly the correct width of the printer. I have been using this in my printer for almost a month with no issues. It stays in place and has not warped or cracked or anything.