Crazy Glue and Loctite 380 are both types of instant CA adhesives, usually referred to as 'super glue'. Regular chain store super glue is usually brittle, and while it bonds to rubber very well, it is not flexible. Loctite 380 is a rubber-toughened with some flexibility, so it's usually the go-to glue to use for bonding o-rings and other rubber that is required to flex a little.