Not a significant Difference in blue and yellow rings - actually found yellow to fit s-35 better than the blue . Also it would be helpful if dimensions/locations of holes from bottom , top , and sides
The 4 hole bushings are horrible quality as on a repair job, it is hard to get the drain pipes perfectly fitted into the bushings , thus they leak. A better system would have been 4 couplings molded into the box and drainage pipes join to the coupling. Even with loads of putty, still will drip, drip. Box could be a little bigger in dimension also.
Solid construction, heavy duty materials, totally satisfied!