3D Printing enthusiast shop and weblog Proto Paradigm offers many free designs (things) for use with mason jars at Thingiverse, a depository of free 3D printer designs, including regular and wide ...

The lids, which are more like holders that screw on top of the jar, are 3D printed, using bioplastic packaging waste from a Dutch startup called Reflow, which collects plastic from recyclers and ...