The trailer called "Montis" is a trailer for mountain bikes. I developed it thinking about practicing outdoor activities and for adrenaline lovers. The trailer Montis provides essential camping equipment to spend the night in almost any type of terrain and to enjoy the company of friends. It's airless tire provides an easy and pleasant drive since its inner structure "honeycomb" absorbs shocks, acting as a giant damper. It also has the characteristic to adapt to any irregularities of terrain. There is also a dynamo system within the wheel which carries a lamp and small devices such as mobile phones. This way the user is ready for any circumstance. The shape of the entire trailer was designed and developed to reduce the production cost by using some parts which are left over on the market. The wheel itself may be replaced by any other bicycle wheel, on condition that it has the same diameter.