"I was confident of success because I had used longer versions of this fixing before. But it failed to work in the two applications that I had bought it for this time (but through no fault of the product).
I needed to fix down a permanent gazebo to natural Indian sandstone slabs which varied in thickness from 25mm to 40mm. But the 60mm nylon inserts were only split and internally tapered to expand over the last 32mm of their length, so some of the fixings had their expanded part hovering in the void (or weak mortar) under the slab, and turned freely even when fully tightened.
My second failure was mounting garage wall storage units to a brick wall. I inserted the nylon insert into an 8mm hole and then passed the hammer-screw through the mounting hole in the back of the wall unit. Accessibility problems meant that it was not possible to hammer the screw in, and the nylon insert was so loose in the hole (drilled accurately with a new DeWalt 8mm Extreme 2 masonry drill bit) that it was not possible to start the screw.
Rather than bodge either job with wedges, I resorted to using Fisher Universal Nylon Plugs UX8x50R with 12 gauge x 50mm stainless steel self-tapping screws. That gazebo and those wall units are now FIXED!"