Use the Bathmate Long Insert for Hydroxtreme11 Penis Pump once you have started to measure noticeable results from using the Bathmate Hydromax pump. This insert has been specifically designed for this Bathmate model. It helps maintain a perfect fit for your new-found length and girth so that you don't have to completely replace your Bathmate pump system. The Long Insert prevents the penis from getting caught in the bellows once erect and helps maintain an air-tight seal between you and the Bathmate penis pump. Only use the Long Insert when the original, shorter length tube becomes too small to comfortably accommodate your penis.