Printed from rubbish, deliberately.
The filament is reclaimed PETG — post-consumer drink bottles and the spool waste the filament industry makes for itself — reprocessed rather than pressed from new pellets.
It was chosen on merit before it was chosen on principle. A 0.42 mm PLA shell is genuinely fragile; PETG is tougher and far less brittle, and softens twenty degrees later, so a sunny windowsill stops being something to think about. If it were worse to own, it would not be here.
It does cost something, and the cost is time. The same shade takes roughly two to three times as long on the machine in PETG as it does in PLA — it needs more cooling between layers, and a wall this thin has nowhere to lose the heat. That is a real constraint, not a talking point: it is why the range is six shades rather than sixty, and why nothing is printed before somebody has bought it.
One honest consequence. Reclaimed stock varies slightly from batch to batch, so two shades bought months apart may not match exactly. That is what reused material looks like, and it is why every colour here is described by what it does to the light rather than by a swatch.