The openings come with shower doors slide or swing. The sliding shower door bottom seal mostly do not use a gasket bottom. The doors of shower swing outward, moreover, scanning using a gasket to seal the door opening and prevent the water from escaping below. The door gasket can connect with an adhesive that is screwed to the door or you can simply slide in and out of a channel bottom.
Open the shower door bottom seal and look for the screws that hold the retainer base gasket on the door. Remove the screws with a wrench or a Phillips screwdriver and remove the seal retainer out the door. If your stick has no screws, making the end of the door seal with a pair of needle nose pliers and pull the seal channel bottom out.
Unroll the new shower door bottom seal and cut to the length of the old gasket with a pair of scissors. If the seal retainer is secured with screws, put the old gasket against the new seal. Click holes in the new seal with the tip of the scissors with the old gasket as a template. Insert the screws through the seal and gasket positioned at the ends of the screws.