This is my ratty ~0.9 - 1.1 pound weighted shift knob. Mishimoto's top rated one is 0.8 pounds and most are slightly heavier. Feels great shifting with it weighted. The shifts are easier and smoother.
All the parts were salvaged (free): skateboard wheel found in the street, plumbing line weight leftover from a sink remodel, two found nuts. I pressed one nut into the back of the wheel to "thread" the knob, tightened the weight in place on the shifter, and screwed the wheel down onto the weight. I used the second nut as a locking nut.