CycleOps Mag Plus Cycling Trainer With Adjuster Magnetic resistance unit provides a quiet and frictionless ride; Linear resistance boosts workout intensity to match each pedal stroke and gear click Noise level at 20 mph is 70-74 decibels; Precision-machined alloy roller reduces tire wear and slippage Adjust tire fit to resistant unit with a convenient turn knob Made in madison, wi, USA Lifetime Warranty Includes a bar-mounted remote shifter Not compatible with 29'ers Redesigned to deliver even more resistance