CAP – The GESIPA CAP cup blind rivet is inherently air- and watertight. The construction: For technical reasons, the mandrel of the CAP blind rivet must be fixed in the hollow rivet. As a result, the rivet body can only deform slightly during the setting process. Consequently, a cup blind rivet has only marginal hole friction properties. However, these are necessary to compensate for larger hole tolerances. With care for a tight connection: When the GESIPA CAP blind rivet is processed carefully, it provides the basis for a reliable "tight" connection. The technical requirements make very careful preparation in the application essential. The hole diameter should be as tight as possible to ensure flawless functionality in the application over a long period.