Does the NGK CR9EIX fit the Aprilia RS4 125 (2011–2020)?
Yes — the NGK CR9EIX is a correct fitment for the Aprilia RS4 125 (2011–2020).
Last verified: 22 July 2026 against 2 independent sources (NGK UK Motorcycle Catalogue 2022 (official PDF), Sportsbikeshop fitment catalogue).
Brakes are safety-critical. Always confirm fitment against your owner's manual before purchase and installation.