Portability & Space Saving, High-quality Material. Retractable Capacity. This Water Cup Adopts a Retractable Design, & the Capacity Can be Adjusted According to Your Needs. You Can Choose the Size of the Capacity According to Your Needs, Which Not Only Saves Space But Also Meets the Drink Water Needs of Different Occasions. for Example, When Climbing a Mountain, You Can Choose a Smaller Capacity to Lighten the Load; While Traveling or Working, You Can Choose a Larger Capacity to Meet More Drink Needs. Customizable. as a Business Gift, the Water Cup Can be Customized. You Can Print or Engrave Your Company Logo, Brand Name or Personal Message on the Water Glass to Make It a Unique Gift.