Inclusion Criteria:  Patient scheduled for ureteroscopy and laser lithotripsy Non-obstructing renal stone 2 cm total stone diameter (if multiple stones, then sum of maximum diameters) or less undergoing flexible ureteroscopy age > 18 years  Exclusion Criteria:  age < 18 years pregnancy status =positive indwelling nephrostomy tube severe hydronephrosis that in the opinion of the investigator, will make it challenging to make the patient stone free