I ordered the wrong thing. They are exactly the same as the first 20 just smooth on the top. What I like about these (and the ones I was using before) is they will accept a wider bushing; 8mm vs 7mm like everyone else uses. I'm all set up with peek and all the
threading equipment and gadgets to make 8mm work, 7mm would require retooling, now if I could just find a 510 with a m8 X 1.0mm threaded throat..... 8x 0.50 thread is a pain. The 510s by them selves take almost as long to build as the rest of the
mod all together. I will look into the new one that Inspects and
nautilus keep hounding me about...... Lol