"CYCLUS TOOLS cable stretching/holding pliers (aka, cable third hand), with rubber handle.
When pretensioning the brake cable on your mechanical rim brake, these tensioning/holding pliers are a helpful third hand for assembly and brake setup.
Simply grab the the inner cable of the brake with the cable pliers, pre-tension it and then lock it with the sprung lever to clamp the cable firmly while adjusting the brake lever and caliper.
Details:
CABLE STRETCHING PLIERS