I used this on two different racquets and quickly found that a hair dryer (tried two different dryers) really takes a while since it just doesn't seem to have high enough temperature. I bought a cheap, basic heat gun for about $12 at Harbor Freight and worked quickly in shrinking the wrap. I needed more than a 1/8 size change so I put two on each handle. Be warned that if you put two or more on, you will start to lose the angled ridges that make your grip hexagonal - it will start to become more like an oval with less pronounced ridging. Other than that, this does exactly what it says it will.
Worked perfectly as advertised. I applied two sleeves (separately) to bring a 4 1/8 grip up to a 4 3/8 inch size. Be patient applying the heat. Start on Low Heat Setting, then slowly increase the heat to get the temperature setting that works best for your heat gun.