Top metal was used for this thumb. Extremely heavy duty and ready to work. Very happy i made this purchase and the price point was unbelievable. Packing did not leak once in use. Connection hydraulic hoses did not leak and have not done so since. I have removed 70+ stumps (Pine) and lost track of how much brush moved with it.
While this isn't as nice as a factory thumb, it is definitely built heavier. The frame, cylinder, and thumb are large, strong and have a good range of motion. I installed on a 60 series excavator and it fits, but just barely. Would be great on a backhoe or 80 series machine. Overall, I'm very happy with it.
Shawn Nemec 
