Abstract: The invention relates to a biocompatible, low-viscosity, radiation-curable formulation for producing medical products, in particular adaptive ear pieces, otoplastic parts, shells or ear parts, by means of PNP methods or stereolithographic methods. Said formulation comprises: a) 15-60 wt. % of a monomeric or oligomeric dimethacrylate based on bisphenol A or bisphenol F; b) 0-50 wt. % one or more monomeric or oligomeric urethane (meth)acrylates with a functionality n<4, a viscosity <30 Pa s and a molecular weight <3500; c) 2-25 wt. % of a monomeric, aliphatic or cycloaliphatic dimethacrylate with a viscosity <3 Pa s; d) 2-35 wt. % of an iminooxadiazone dion derivative, characterised by 3 methacrylate and/or acrylate functions; 0-15 wt. % one or more monofunctional methacrylates; f) 0.5-6 wt. % of a photo initiator or a combination of photo initiators, whose absorption lies in the wavelength range of the laser beam that is used or the irradiation source; g) 0-0.5 wt.