Slim Pure White Performance Tubing is compatible with CPAP & BiPAP machines -- like the System One 60 Series and ResMed's S9 Series -- that have a setting option for 15-MM Tubing. Slim Performance Tubing is 20% lighter and much more flexible than standard tubing. Its ultra-light design provides a more forgiving connection to your machine so it is less likely to pull on your mask and disrupt the seal! This tubing is approximately 6 feet long and has an inner diameter of 15mm.