Easy install after I understood the instructions. Only the stretchy part attaches to the watch. I have exactly 18 mm exposed of my pins and it's a perfect fit. It fits and looks great! If your pins are (exposed) only 16 mm I think it will be snug to squeeze in the attachment part but should work, if you have 20 mm there will be some give on the sides, 18 is perfect. The watch is attached to a stretchy part so if you were to ding or get your watch stuck someplace there is plenty of give and the pins should hold up. The strap will never give! I think I can hang my almost 200 LB on it!? I also like that the band widens and is soft just under the watch, the metal backside does not touch my skin and it's comfortable. Only negative is that if you don't have a tiny arm some Velcro will be exposed to catch dust, dirt, (plant seeds in my case), etc.