I bought these plastic range tee's to practice using a new driver i had recently bought. Having never used a driver, i was looking for a range of tee heights to help discover the best way for me to make a connection with the club head. The largest tee is ideal for the club, and its height has subsequently determined the heights that i now set my tee when on the course. The other two tee's in the bag have also helped my iron play on par 3's and riskier par 4's. I recently played a couple of rounds of golf, and managed to increase my stableford score 11 points after using the new tee's...I'm sure a bit of practice also played its part, but its a very good product at a reasonable price!