Hi Derya, no where in our description for Upper Colorado Rafting does it mention Class IV and V rapids. Even for whitewater rafting that's typically called Intermediate-Advanced Rafting.
It also shows that the Upper Colorado is located 1 hour and 30 minutes from our adventure park/start point.
We always advise guests to do their due diligence when it comes to booking activities. Had you informed us you were interested in Int/Adv whitewater rafting we could have switched your trip.