Abstract: The basic component of the device is a bent tube. The included angle between the tube portions on each side of the bend is in a range of 90.degree. to 130.degree. with 110.degree. to 120.degree. preferred. The tube portions on opposite sides of the bend are of unequal lengths, 8 inches and 22 inches being an example. A stop is attached to the longer portion approximately two inches from the bend and extending into the included angle. The stop is triangular in plan form. The end of the stop facing the bend is at an excluded angle to the tube surface in a range of 90.degree. to 150.degree. with 135.degree. preferred. The height of the stop is in a range of 1/4 to 3/4 of an inch. The other sloped face is at an included angle with the tube surface in a range of 10.degree. to 30.degree.. Clamping apparatus is provided which is adjustable to prevent or allow linear relative motion between a line threaded through the tube and the tube. There may be an additional bend in the tube.