We recommendto use the upgraded version with the ball, which increases vacuum and comforsca How the water pump works?     The water pump is an external penile rigidity device which uses vacuum technology to improve and maintain erection quality and duration through regular exercise of the penis.     The water pump functions by creating a vacuum seal against the pubic area of the user ,enclosing the flaccid penis.When the pump is pushed downwards against the body,the bellows compress and water is ejected from the end of the pump via the open valve.When released the bellows expand and the valve closes,creating a partial vavuum inside the pump.This causes the penis to expand and fill with blood,creating an erection.Re pumping increases the size of the erection. Comparison of advantages of water pump and air pump：     The pressure created by the air is unstable and creates an uneven vacuum that can cause the penis to bend and bulge.However the pressure created by the water is balanced and stable, and as the water drains, it creates an even vacuum around the penis and allows for expansion without damage such as bending and bulging. X5, X7, X9 pumps belong to water pumps X5/XX20、X7/XX30、X9/XX40 water pump size：     X5/XX20 pump ：1.96inch*7.48inch （Suitable for penile erection length less than 15cm）     X7/XX30 pump：1.96inch*8.66inch (Suitable for penis erection length greater than 15cm and less than 18cm)     X9/XX40 pump：2.56inch*9.84inch (Suitable for penis erection length greater than 18cm and less than 22cm) There would be some difference as it was measured by hand Xtreme pump full set The material is made of environmentally friendly plastic and silicone, which can be used with confidence Product detail presentation X5/XX20 X7/XX30 X9/XX40 pump Instructions:     1. Can be used in both bathtub and shower scenarios, please adjust your body to a fully relaxed state in warm water before use.     2. Use your fingers to push the top valve lever into the far left or far right that the closed position. Remove the comfort insert (to prevent trapped air), and place the pump upside down under the shower until full of water.     3. UInsert the comfort insert into the pump fulled with water to prevent air leaks.     4.Place the pump over your flaccid penis tight up your pelvicseat with the valve in the side(closed) position.The chamfer can bepositioned facing either upwards or downwards depending on your level of comfort.     5.Make a seal against your body,ensuring that the positioning is comfortable and that your testicles are well clear.     6.With the pump angled slightly upwards,ensure that the valve switch in the central(open)position and commence pumping.     7.Ensure that the valve switch is in the central(open) position when pumping.      8.Pump slowly and evenly until the bellows remain depressed,indicating that optimal vacuum has been achieved     9.We recommendto use the upgraded version with the ball, which increases vacuum and comforsca     10.The duration of use within 24 hours should not exceed 15 minutes. It is recommended to repeat 3 sets within 15 minutes. Each setlast for  4-5 minutes. After a 1-3 minute rest, continue to the next set. Do not overuse.     11.When the device needs to be removed, the valve switch in the middle needs to be lifted slightly to release the vacuum.Then the pump will be easily separated from the body. About the package: send privately 1.WORLDWIDE SHIPPING. (Except some countries and APO/FPO) 2. Orders processed timely after the payment verification. 3. We only ship to confirmed order addresses. Your order address MUST MATCH your Shipping address. 4. The images shown are not the actual item and are for your reference only. 5. If you have not received your shipment within 45 days from payment, please contact us. We will track the shipment and get back to you as soon as possible with a reply. Our goal is customer satisfaction! About payment: Buyer pays tutorial below: https://service.aliexpress.com/page/knowledge?pageId=37&category=1000021991&knowledge=1060062451&language=en