Double DU sealed bearing desnstrong lubrication performance and can effectively protect the pedals from water and dust.Antiskid pins on each side provide more secure on the pedals and make the feet have great grip.The mountain pedals set are made of aluminum alloy material hhstrength and excellent in wear resistance and durability.L is used for the left pedal Ris used for the rht pedal Before you install the new pedals look for the L and R marking on the axle.Standard 9/16 inch spindle are suitable for most bicycles. Such as BMX/MTB/Cruisers City/Hybrid/ Urban/Folding bicycles etc.