ADDS HEIGHT TO YOUR AEROBARS – The Bike Aero Bar Risers are designed to add either 15mm (one spacer) or 30mm (two spacers) of height to your Redshift Quick-Release Aerobars for a better fit. OPTIMIZE YOUR FIT FOR PERFECT COMFORT – The bike aero bar extension riser kit adds height to your aerobar extensions and arm pads allowing you to optimize your fit for perfect comfort in the aero position. COMPATIBLE WITH – Compatible with Redshift Quick-Release Aerobars purchased after January 2020. If your Redshift aerobars were purchased before Jan 2020 your dovetail clamp will be 12mm tall and you will need a different riser kit. INCLUDES– Four spacers included (2 per side) and all necessary mounting hardware to rise either 15 mm - one spacer per side; or 30 mm - two spacers per side. SUPERIOR QUALITY AND SATISFACTION – We stand behind the products we sell and want you to have an amazing experience with your Redshift bike accessories and parts. All our products come with a lifetime warranty.