This is a single center, single arm non-randomized study of 48-hour CGMIS wear duration incorporating two meal-challenge tests to explore the performance of a single insertion combined glucose-sensing insulin delivery cannula.

Inclusion Criteria:

• Type 1 diabetes, present for at least 6 months. If there is lack of clarity regarding the type of diabetes, the PI will make the final decision based on medical records.
• Age 18-75
• Currently using a Tandem T-Slim or Medtronic 523/723 or newer series insulin pump to treat their diabetes.
• Hgb A1C between 5.8 and 10%
• Willingness to follow all study procedures and to attend all clinic visits.
• Willingness to sign informed consent and HIPPA documents.

Exclusion Criteria:

• Need for MRI/CT/Diathermy during study participation
• Current use of Hydroxyurea
• History of chronic kidney disease
• Inability to read pump or CGM display due to reduced visual acuity
• History of unstable ischaemic heart disease or myocardial infarction within the last 3 months.
• History of chronic liver disease
• Active infection such as HIV or hepatitis
• Anemia defined by HCT at least 4 percentage points below lower limit of the reference range
• Dementia, Schizophrenia or other untreated mental illness
• Chronic substance abuse
• Chronic alcohol abuse
• Seizure disorder
• Major surgical operation within 30 days prior to screening
• History of bleeding disorder or treatment with anticoagulants.
• Allergy to acrylate-based skin adhesives
• Ongoing use of an investigational drug or device
• Female of childbearing potential who is pregnant or intending to become pregnant
• Diabetic ketoacidosis or hypoglycemia requiring hospitalization within the last 6 months
• Insulin resistance as defined by insulin requirement of more than 200 units per day
• Use of glucose-lowering medications other than insulin
• Need for uninterrupted treatment with acetaminophen
• Any other physical or mental condition judged by the PI as being exclusionary.