The North Face Class V Convertible Pant
Here's what other sites are saying:
Minimize the amount of stuff floating around the tent and pack light with The North Face Boys' Class V Convertible Pant. Your boy will only need this one pair of pants for the family camping trip, thanks to its quick-drying fabric, comfortable, functional design, and, of course, the easy convertability between pants and shorts.
When cool mornings heat up, the quick-drying Class V Convertible Pants can be worn as shorts...and when boys grow, the length can be extended with The North Face EZ Grow cuffs.