1st version in PETG broke on hard crash. Now have reprinted with nylon (Taulmans 910 Alloy) with 3 shells and less infill (20%). Frame weighs 9g. Fitted with racerstar motors (used vinyl electrical tape wrapped around motor base - had troubles printing the original holders). Wraps of tape allow a very snug and precise fit. Fitted big 65mm props (rolling spider type) for huge thrust. 600mah battery gives me 4-5mins flight time. Nylon seems strong - took some hard hits into soccer goals and survived.