Harry,
The rubber bulb holders are fine and provide a good replacement for the original BS items.
Just be aware, when mine came the wires from the two bulb holders had been paired about 3 inches from the holders with only twisted wire joints
.
Not a problem for use on the BS because you have to separate them anyway and solder on the correct wires but if used as they come on another make of bike, I would strip off the tape and solder the joints.
Still a great find and reasonable price.
Brian.