With the new design visible weld style titanium coupling, the lugs press into the tube and are then welded in place. When the coupling is screwed together, the nut, the built-in rings, and the welds are visible. The advantages of this coupling over the hidden weld coupling are that it's easier to install and it's a few grams lighter. The disadvantage is that the welds are visible. A photo of the installed coupling was provided by Moots Cycles. To calculate the weight increase resulting from adding couplings to a frame subtract the weight of the 1 3/4 inch (actual 1.780) long piece of tube removed for each coupling added. The "machine to fit" or zero wall couplings are designed to be machined by the frame builder on the outside of the coupling in the area that gets pressed into the tube. For example, the 1 1/4" "machine to fit" coupling will fit tubes with a wall thickness as thin as .017" or as thick as .045" or anything in between. (.43mm to 1.14mm).