Minoura Mag Riser 3

Every stationary trainer lifts up the rear wheel to enable to spin the wheel. If you train in this strange position, you will have to apply unnecessary force to the handlebar to support your upper body. It's not good for effective training and for learning correct riding position. You should sit on the saddle and relax the arms.
Mag Riser is a plastic block to level the bike by putting it under the front wheel.