THREE PACKS IN ONE PACKAGE FOR N20 - 3 PC of durable and affordable 18.5 inch short tubes in one set satisfies your long-term need! Replacing every 3-6 months is suggested. | REDUCE AIR LEAKS & NOISY SOUND - Three parts rotatable design ensures a snug fit between the short tube and other components, reducing air leaks and annoying air noises to improve sleep quality for you and your companion. | UPGRADED FOR DURABLE SHORT HOSE - The material of the short hose is improved to reduce the elasticity of the short tube, which makes it harder and stronger, not easy puncture. | QUICK-RELEASE ELBOW - Everness’ replacement short hose allows you to quickly disconnected and installed, which is convenient for you to walk around after you wake up at night. | PERFECT COMPATIBILITY - Perfectly compatible with your frame. The upgraded short tube changed the original stepped exhaust structure to make the vent holes more convenient to clean, but still retain the same size and number of vent holes as branded elbow. | PATENT PROTECTED - This product is protected by US Pat. D1,035,861 S; Enjoying reliable, durable performance that stands out in quality and innovation