The park tool vc 1 valve core tool is a small handy tool designed to remove and install schrader and presta valve cores and to remove and install presta valve extenders with 5mm wrench flats park tool vc 1 valve core tool features small handy tool designed to make extracting schrader and removable presta valve cores and valve extenders simple 5mm wrench flats provide additional leverage especially useful when removing cores that have been used with sealant a perfect 39t