Park Tool Adjustable Cup Wrench HCW-11

The HCW-11 fits slotted bottom bracket adjusting cups and cups with raised 16mm wrench flats. These are common on older English bicycles and less expensive bicycles. The opposite end has two ears that are 23mm wide and approximately 5mm wide.

WARNING: California Proposition 65

This product contains chemicals known to the State of California to cause cancer, and birth defects or other reproductive harm.

https://cambriabike.com/pages/warning-california-proposition-65