Can I use two trash bags at the same time?
Of course you can. Simply adjust the roll length with the wheel.
Can I only attach this trash dispenser to the headrest?
No, you can also attach it to any surface where the included strap will hold. But we recommend using a headrest as that is how this item was designed to be installed.
Are garbage bags included
Together with the dispenser, you get a roll of 20 thick and waterproof PE trash bags.