A: No. In fact, they're designed for when you don't need extra protection from heat, chemicals, abrasives, or other harsh environments. This heat-shrink tubing is generally for lighter-duty uses, such as insulation, wire identification, wire bundling, mechanical protection, lightweight harnessing, physical/electrical protection of components, strain relief, and solder insulation.

A: Yes, because it still shrinks at a 2:1 ratio, meaning that it will still create the same tight hold as much thicker heat-shrink tubing in the same ratio. The advantage is that it won't be as thick on the outside, so won't take up as much room in your wiring job.