My nipple size is 13mm, I will need a smaller size flange than 19mm, am I still be able to use Hegen PCTO™ Double Electric Breast Pump (SoftSqround™) Device?

Yes! If you have a nipple measurement of 13mm (13mm + 4mm = 17mm), you will need to purchase a 17mm flange insert and place it onto our 25mm flange and you are good to go!