To explore the mechanical properties afforded by our elastomer resins, we conduct uniaxial tensile tests to quantify the extensibility of the 3D printed elastomers. As the crosslinker concentration decreases from 2.5% to 0.3%, the elastomers become softer and more stretchable, with Young's modulus decreasing from 278.8 kPa to 20.3 kPa and tensile breaking strain 𝜖 𝑓 increasing from 76.4% to 1355.6% (Figure ). The values of Young's moduli are comparable to those of molded samples, which increases linearly with crosslinker concentration (Figure , Table , and Table ). Notably, the printed samples often exhibit a higher tensile breaking strain than the molded ones, which are, respectively shown by the filled and empty circles in Figure . For instance, for the elastomer with 0.3% crosslinker (S0.3), 𝜖 𝑓 is 891.8% for the molded sample; by contrast, the printed one exhibits a remarkably high 𝜖 𝑓 of 1355.6%, as visualized by the photos in Figure .