Magnetic trainers also called mag trainers use adjustable magnetic resistance to create drag against your bike's rear wheel. The flywheel has rotating magnets that create a set amount of resistance as they're engaged. To increase or decrease the amount of resistance you must shift the gears of your bike or dismount your bike and adjust on the trainer with a resistance knob. Know that using a trainer like the Deuter Bike Trainer inside means that you "lose" the environmental resistance factors like the wind inclines and other road conditions. Also keep in mind there is noise associated with riding your bike indoors on a cycling trainer! Sound acts differently off walls/ceilings than it does outside on the road. Some ways to combat this are to use an exercise/trainer mat or replace the bike's rear tire with a slick racing tire.Bikes with quick release structure works bikes only have bolts on rear wheels also works some old model bikes dont have quick release structure. Package includes. x1 Bike trainer. x1 Quick release skewer. x1 Front wheel riser block. x1 User guide setup tools.