The International Diabetes Closed Loop (iDCL) Trial: Protocol 1

Inclusion Criteria: 1. Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year and using insulin for at least 1 year 2. Use of an insulin pump for at least 6 months 3. Age ≥14 years old 4. HbA1c level \<10.5% at screening 5. For females, not currently known to be pregnant 6. Willingness not to add glucose-lowering agents (such as Pramlintide, Metformin, GLP-1 analogs, SGLT2 inhibitors) during the study 7. Willingness, if not assigned to the closed-loop group, to avoid use of any closed-loop control system for the duration of the clinical trial 8. Willingness to suspend use of any personal CGM for the duration of the clinical trial once the unblinded study CGM is in use 9. Willingness to establish network connectivity on at least a weekly basis either via local Wifi network or via a study-provided cellular service 10. Currently using no insulins other than one of the following rapid-acting insulins at the time of enrollment: insulin lispro (Humalog), insulin aspart (Novolog), or insulin glulisine (Apidra) 11. Investigator has confidence that the subject can successfully operate all study devices and is capable of adhering to the protocol 12. For subjects less than 18 years old, living with one or more parent/legal guardian (referred to subsequently as diabetes care partner) committed to participating in study training for emergency procedures for severe hypoglycemia and able to contact the subject in case of an emergency Exclusion Criteria: 1. Medical need for chronic acetaminophen 2. Use of any glucose-lowering agent (such as Pramlintide, Metformin, GLP-1 analogs, SGLT2 inhibitors) in the 3 months prior to enrollment 3. Hemophilia or any other bleeding disorder 4. A condition, which in the opinion of the investigator or designee, would put the participant or study at risk including any contraindication to the use of any of the study devices per FDA labeling 5. Participation in another pharmaceutical or device trial at the time of enrollment or during the study 6. Use of a closed-loop system within the last month prior to enrollment 7. Employed by, or having immediate family members employed by TypeZero Technologies, LLC