Omnipod Horizon™ Automated Glucose Control System Preschool Cohort

Inclusion Criteria:

   1. Age at time of consent 2.0-5.9 years

   2. Living with parent/legal guardian

   3. Diagnosed with type 1 diabetes. Diagnosis is based on investigator's clinical judgment

   4. Deemed appropriate for pump therapy per investigator's assessment taking into account
   previous history of severe hypoglycemic and hyperglycemic events, and other
   comorbidities

   5. Investigator has confidence that the subject and/or parent/guardian/caregiver can
   successfully operate all study devices and is capable of adhering to the protocol

   6. Willing to use only the following types of insulin during the study: Humalog, Novolog,
   Admelog or Apidra during the study

   7. Willing to wear the system continuously throughout the study

   8. Willing to participate in challenges for 2 consecutive days, consisting of a minimum
   of 3 hours of activity per day and dietary challenge by reducing the number of
   carbohydrates entered for a given meal by 50%

   9. A1C <10% at screening visit

10. Subject and/or parent/guardian must be willing to use the Dexcom App on the Omnipod
   Horizon™ PDM as the sole source of Dexcom data (with the exception of the Dexcom
   Follow App) during the hybrid closed-loop phase

11. Subject and/or parent/guardian is able to read and speak English fluently

12. Has a parent/legal guardian willing and able to sign the ICF.

Exclusion Criteria:

   1. A medical condition, which in the opinion of the investigator, would put the subject
   at an unacceptable safety risk

   2. History of severe hypoglycemia in the past 6 months

   3. History of DKA in the past 6 months, unrelated to an intercurrent illness, infusion
   set failure or initial diagnosis

   4. Diagnosed with sickle cell disease

   5. Diagnosed with hemophilia or any other bleeding disorders

   6. Plans to receive blood transfusion over the course of the study

   7. Clinical evidence of acute or chronic kidney disease (e.g. estimated GFR < 45) or
   currently on hemodialysis

   8. History of adrenal insufficiency

   9. Has taken oral or injectable steroids within the past 8-weeks or plans to take oral or
   injectable steroids during the course of the study

10. Unable to tolerate adhesive tape or has any unresolved skin condition in the area of
   sensor or pump placement

11. Plans to use insulin other than U-100 insulin intended for use in the study device
   during the course of the study

12. Use of non-insulin anti-diabetic medication other than metformin (e.g. GLP1 agonist,
   SGLT2 inhibitor, DPP-4 inhibitor, pramlintide)

13. Thyroid Stimulating Hormone (TSH) is outside of normal range with clinical signs of
   hypothyroidism or hyperthyroidism

14. Currently participating or plans to participate in another clinical study using an
   investigational drug or device other than the Omnipod Horizon™ Automated Glucose
   Control System during this study period

15. Unable to follow clinical protocol for the duration of the study or is otherwise
   deemed unacceptable to participate in the study per the investigator's clinical
   judgment