I got these to wear under jeans on cold days and they are very long. You can wear a regular pair of underwear below them and they are very close to being leggings, so they fit nicely into any pair of pants you want to wear. They have a drawstring around waist  but no opening in the crotch area. They also made a heavy weight version for colder days. These are the "Varitherm" type from Duofold.