It was the stock crank on a Prophet 4000 mtb. If I remember right, it was a FSA K-Force carbon crank.That thing was't worth a darn for me. I kept ripping the left crank arm off, happened a couple of times. FSA came out with a longer bolt to secure the left arm, LBS locktited it on. All was good for a few months, then I folded the middle chain ring over. Trying to take the left crank arm off, the bolt securing it rounded out, it was made of aluminum. So I hacksawed it off and threw the whole thing in the garbage. Put a XT crank on and never had another problem. When we took it apart the last time we found the bearings destroyed in the bottom bracket.