Completely waterproof patented protection for PICC lines. Comes with pump to remove air and create a vacuum-seal. Once air is removed, drypro can't be taken off unintentionally and water can't get inside. Bathe, shower, or even swim without worry of infection or damage to PICC site. Sizing instructions: IMPORTANT: To ensure the DRYPro protector is airtight and waterproof it is important to take the proper measurements to determine the right size. Measure the circumference of the arm about 2" above the site of the PICC line and the circumference 2" below the site. Once you have the measurements, follow our size chart and pick the PICC cover size that falls closest to the center of the circumference range. You'll see the inside file shows steps on how to customized the PICC cover for a comfortable and correct fit. This is important. If one of the openings of the waterproof cover is too small or tight, you can trim a tiny bit off the opening to make it wider. We do not recommend trimming more than a 1/4" at a time. If you cut too much you risk not being able to create an air tight vacuum seal.