For most Nespresso machines (manufactured after 2010) a sealing ring must be applied to the capsule in order to seal the capsule holder. With each capsule two sealing rings are provided. This set of 10 sealing rings is a pack of spare parts.
The sealing ring is best rolled onto the closed capsule until it rests on the rim of the lid, as demonstrated in this video
You can leave the cover the seal ring after brewing and cleaning the capsule. The sealing ring should be removed only if you want to clean the capsule in the dishwasher or with abrasives. Each seal ring holds so for at least 500 applications.
