What is a connector protection cap for an indwelling needle

It is a small plastic or rubber cap used to protect the connector of an indwelling needle. An indwelling needle is a medical device used for prolonged infusion or administration of medication, and usually has a fitting at the end for connecting to an infusion tube or syringe. In some cases, when an indwelling needle is not being used, the fitting protection cap can be used to close it in order to avoid contamination and protect the fitting.