Depending on the dimensions of your doorjamb, you may need an extra large strap. This product listing gives you the opportunity to order additional straps for your U-Fix so that when you encounter a larger doorjamb you can still have the ability to use the U-Fix.
Measure one side of your trim
2.25"-2.50" trim = 13.5" strap
2.50"-3.25" trim = 15" strap (Standard, fits most doors)
3.25"-4.25” trim = 17" strap
4.25”-4.75” trim = 18" strap
4.75”-5.25” trim = 19” strap
5.25”-5.75” trim = 20” strap
The following video link will direct you on how to measure the trim on your door in order to select the right size:
https://vimeo.com/336018903