"Hi, this is just a set of TPU tires for the Balloon Powered Single Cylinder Air Engine Open Chassis from gzumwalt. [ https://www.thingiverse.com/thing:2870929 ] Print as is in TPU and replaces the original 4 "AS568" #219 o-rings Enjoy!" - caru3D
You also can go to this link and check it out: https://www.thingiverse.com/thing:2888341
Nice Post