You are very fortunate. The only type of rear blades or really any ground engaging implements around here on CL is lightweight stuff. And then a lot of them are bent or damaged in some manner. I looked for months for a medium duty box blade of any type and all I found was what I consider to be junk at 75% of new prices. I ended up purchasing a new Dirt Dog 72" ROBB, 710#. It works well on my heavy clay, very rocky property and those typical TSC, Agri Supply and most farm store pieces would not have been able to do the job.