I need the strain relief that holds the cable to my house. The clerks at Lowes/HD have no idea what I'm talking about. It crimps to the cable and is then attached to the side of the house, giving some slack in the cable. The electrical service has these too, but the one for my cable service was hit by a branch. And I'm not a cable customer so I doubt they'll rush out here to fix this for a non-customer. Right now the cable is just hanging down on the ground.
Electrical supply store only?