These belts are for my John Deere 300 garden tractor mower deck. OK, so I have not used the M41668 deck belt, yet, but I did use the M45254 belt I also ordered for the deck mule drive, It has a very rigid feel to properly work with the twisting going around the mule idler pulleys. I had gotten a belt at our local "tractor" store about a month ago when my old JD belt gave up the ghost. I could tell right away that it was OK short term but wouldn't last, it was too "flimsy" and seemed to easily stretch from the start. The new Aramid belt is much stiffer and, so far, is working perfectly.