What kind of pants does Bob wear?

I always thought they were sweatpants but they have pockets and a fly. They’re sturdier than sweatpants. And he’s changed into sweatpants that look more like sweatpants in several episodes. They don’t really look like chefs pants and he wears them in his days off and to his accountants office lol He doesn’t seem like the type to wear gray jeans. What is he wearing?!?! lol