We just got back from a 2 day ride, that consisted of about 1000 miles. The first day was 95 to 97 degrees and the 2nd day was 97 to 99 degrees. The water stayed cold all day. It made the trip easy to stay hydrated while traveling. It also helped keep our core body temp down because the water stayed cool. They are easy to fill and convenient to use. We definitely recommend the Thirsty Rock hydration system. We are believers!