Your VacuGlide's cap requires one of these silicone valves to operate. It is simple to remove by placing a flat head screwdriver underneath it, and gently pressing it up and out. CLICK HERE to watch a video of the valve replacement and removal procedure. If you grip this with pliers or otherwise try to remove it without lifting it by the edge by gentle prying, you will rip it and it will need to be replaced. Two valves are included in each set so you will always have an extra if needed.