Foldable Adjustable Bike Rollers with Resistance for Indoor ExerciseSAFETY & STABILITY: indoor sports safety first, parabolic rollers enhance stability, scientific design makes him safer than straight rollers, choose safer indoor bicycle training rollers. DURABLE & FOLDABLE: High strength and high end aluminium alloy roller bicycle trainer, with three aluminium rollers mounted into an adjustable frame to hold bike wheels. Never worry about our quality. This roller trainer is foldable, handy and save space. LIGHT