The best track system for your Can-am Defender is the UTV 4S1 made by Camso. This is not second hand. We have this machine and it is a fun machine on tracks.
We have mostly used them in the snow, whether deep powder or wet snow these tracks turn your side by side into a totally different machine.
If you need to go in the swamp, muskeg or mud then tracks are a way better then just tires on your UTV. Although you cannot go near as fast.
Remove the tracks for the summer if wanted and reinstall them next year when the snow flies. We have done this for many years.
For towing snow groomers these work fantastic. Even id deep powder. from smoothing snowmobile trails to laying cross country ski trails or any other snow grooming needs the defender with camso tracks does a great job.
We do the sand dunes in Soft sand and this camso track setup does not sink or get you stuck in the sand.