The Schuko CEE 7/7 (combination French and German) plugs I've bought in the past are ABL brand.
Plastic strain relief, but if you are careful and tighten the screws evenly, it doesn't crack and grips the flex jacket very tightly.
The Swiss plug I'm whining about has a plastic strain relief and the cavity is slightly larger than the flex I was using (SJT 18AWG x 3 cord) so while it does grip it, it doesn't grip it tight ENOUGH like I want. The working space is also kind of cramped.
Who remembers those cheap-ass British plugs that used to have a thick CARDBOARD cable clamp?? I'm not kidding!!
I have a couple of these - they've very old -from back when UK plugs didn't have sheathed pins.
