The cycleops mag trainer with shifter is a great way to warm up or down after or before an event or for when the weather is at its worst this simple mag trainer features a spring loaded skewer clamp for secure bike engagement this gives you piece of mind knowing that your bike is safely and firmly in place the trainer has 5 levels of of adjustment which allow for varied workouts and specific workouts which are suited to you when you get going on the trainer the pedals strokes are smooth an