The Park Tool CRS-1 is a professional tool set for installation of 1" and 1 1/8" bicycle fork crown races. Using the long, strong driver tube, one of the included inserts, and a hammer or mallet (not included), the CRS-1 safely and accurately drives the crown race into its properly seated position. The CRS-1 includes six specially-sized inserts – three in the 1" standard, three in the 1 1/8" standard – for compatibility with most crown race shapes and designs. Each insert is made from anodized aluminum to avoid damaging the crown race. The driver tube features solid steel construction and is compatible with forks with up to 340mm of column length. SHIS terminology: The CRS-1 services SHIS sizes 26, 27 & 30. For oversized 1 1/4" or 1 1/2" columns use the CRS-15.2 Crown Race Setter.