"Are you comfortable?"
Translation:Har du det bekvämt?
There are some adjectives that use this have-construction, and then you have to have the det. Another example is jag har det bra lit. ’have it good’ which means something like ”I am happy/comfortable” or like ”the situation is good for me”. It can also be used when bidding farewell: Ha det bra! (Have a nice day/trip etc.)