LBlack14 yep, it's the counterweight and the little allen wrench to take it out, common size too, so if you lose it, no biggie.....a note on the foam oN the stem of the counderweight tha t goes down the shaft to help it fit snug.....I took the CW out before I shipped it and it wedged in the opening and almost fell down the shaft. Grip tape was holding it on the stem....was able to get a needle nose pliers on it and get it out....I'd suggest super glue to hold it in place otherwise that foam will not make it out the opening when removing it in the future. Hopefully that makes sense....wanted to make sure you knew that tidbit if you were going to tinker with the CW.