My M608 came with a broken Z coupler. This is my 2nd printer (1st one was a Printrbot) and both my printers came with these stupid flex couplers broken. I have a spare but not for the 8mm rod size. Do yourself a favor order a spare Z coupler 8mm to 5mm, these things are notorious for breaking in shipping. ALUNAR folks included some spare parts but not this part.