Recently my belt tensioner pulley and arm recently broke on my car, the bearings got all messed up and bent and the pulley itself was bent on the arm of the tensioner which also messed up. My question is, when I went to parts stores to look up this part, they gave my a belt tensioner arm with a smooth pulley similar to an idler pulley, and the one that was on my car was a ribbed pulley (8 rib) I tried looking up pics and i find both smooth and ribbed pullies for the belt tensioner, so which one do I go with????

What came off my car:





And THIS is what I keep getting results for: