I installed another one messed up two times and belkin offer me a replacement I will try another apple store
The devil is in the details here. I got a free replacement of my iPhone 7 glass screen protector from Belkin after the first one developed a chip. No problem there. I took the unopened box to the Apple Store, and they said they would happily install it, but not with the Belkin installer. The reason was that only the Belkin screen protectors in the boxes that Apple carries in their stores have a special holder or frame that fits in the Belkin installer. The Belkin boxes from Belkin or on another retailer's shelf do not have this accessory, so they have to be installed by hand in the usual way, not in the machine.
The Apple Store rep installed my replacement screen protector carefully and there are no bubbles or dust. The only problem is that there is a 1 mm area on the right edge of the active screen and about a 0.2 mm area on the left edge that isn't covered. Otherwise the protector is symmetrically installed if you look at the openings for the home button, the upper speaker and the front camera. IOW, the asymmetry and failure to cover the entire active screen is not an installation issue. I asked the Apple guy whether this is because the 7 has a curved screen, and he said it doesn't have a curve in the active part. My cheapo interim screen protector I used while waiting for the second Belkin protector fully covered the screen, but I couldn't get rid of the halo bubble all around the protector. And I think it wasn't as clear as the Belkin or as smooth, but it cost $6 for two screens.