Inclusion Criteria:  Has type 1 diabetes for more than one year. Subject is on the MiniMed 670G insulin pump therapy within1 year prior to screening. Subject is currently using Auto Mode at least 75% of the time and willing to utilize Auto Mode and Duo device during the study. Subject is willing and able to perform study procedures as per investigator discretion. Subject is willing to take one of the following two insulins: Humalog or Novolog  Exclusion Criteria:  Subject is actively participating in an investigational study (drug or device) wherein he/she has received treatment from an investigational study drug or investigational study device in the last 2 weeks. Subject is female and has a positive pregnancy screening test. Subject is female of childbearing age and who is sexually active should be excluded if she is not using a form of contraception deemed reliable by investigator. Subject is female and plans to become pregnant during the study. Subject has Glycosylated hemoglobin (HbA1c) > 8.5 % at time of screening. Subject has had a history of 1 or more episodes of severe hypoglycemia. Subject has taken any oral, injectable, or IV glucocorticoids within 8 weeks from time of screening visit, or plans to take any oral, injectable, or IV glucocorticoids during the course of the study. Subject is unable to tolerate tape adhesive in the area of Duo™ Extended set or sensor. Subject has any unresolved adverse skin condition, including infection, in the area of Duo™ Extended set or sensor placement (e.g., psoriasis, dermatitis herpetiformis, rash, Staphylococcus infection). Subject has had Diabetic Ketoacidosis (DKA) in the 12 months prior to screening visit. Subject is currently abusing illicit drugs. Subject is currently abusing alcohol. Subject has history of adrenal disorder. Subject has a history of inpatient psychiatric treatment in the past 6 months prior to screening. Subject has any condition that the Investigator believes would interfere with study participation. Subject has a history of visual impairment which would not allow subject to participate in the study and perform all study procedures safely, as determined by the investigator. Subject has a sickle cell disease, hemoglobinopathy; or has received red blood cell transfusion or erythropoietin within 3 months prior to time of screening. Subject plans to receive red blood cell transfusion or erythropoietin over the course of study participation. Subject is using pramlintide (Symlin), SGLT2 inhibitors, GLP agonists, biguanides, DPP-4 inhibitors or sulfonylureas more than 2 weeks from time of screening. Subject has been diagnosed with chronic kidney disease, having an estimated glomerular filtration rate (eGFR)< 60mL/min/1.73 m2, requiring dialysis, or resulting in chronic anemia. Subject has history of cardiovascular disease defined as any ischemic related event or clinically significant arrythmia. Subject has hypothyroidism and has out of reference range thyroid-stimulating hormone (TSH) on screening visit. Subject plans to have medical imagining (e.g., MRI, diathermy services, CT scans, etc.) over the course of the study.