Given that it is with 45 mm diameter tube, which enables to hold more water and speeds up cooling. ^^ The upper and lower covers are high temperature engineering plastics and the transparent part is acrylic. ^^ It is because that such a water is with practicalilty for long-term attraction, thus, you can feel to use it. ^^ Moreover, the upper and lower covers are strong glue seals, and the sealing performance is better than that of ordinary water. ^^ For tight connection, advanced G1/4 thread is equipped, so that it can be safety and leak-.