Children from 6 months to 6 years are randomly allocated into AuraGain group or I-gel group. After anesthetic induction without neuromuscular blocking agent, assigned device in inserted by skillful anesthesiologist. The outcome measures are recorded and analysed.

Inclusion Criteria:

• ASA physical status: 1-3
• age: from 6 months to 6 year
• body weight: 5-20kg
• patients undergoing upper/lower extremity surgery at supine position

Exclusion Criteria:

• patients who do not want to participate in this study
• patients with known difficult airway including congenital facial anomaly or history of difficult airway management
• patients with aspiration risk (gastrointestinal stenosis or stricture)
• patients with symptom of upper respiratory infection on the day of surgery
• patients scheduled for day surgery
• patients judged as not eligible by researchers for other reasons