I bought mine from here just last month. Got it in less than a week and its a OEM Mazda part.
Go to engine and then crankshaft gear.
Heres a pic when I took mine off after I tried to pry it and cracked the edge. I had to use an impact wrench to get it off.
When its on the crank, the center looks like its part of the crankshaft but its not. as you can see its part of the gear.