This is a Bleed Port Screw & O-Ring it for Shimano hydraulic brake levers.

Features:

• Replaces lost or broken bleed port screw & o-ring
• Take care when installing. Do not overtighten. It is very easy to strip
• 105 and Dura-Ace/Ultegra screws can generally be used interchangeably; however, the hex key size required may be different

Compatibility:

• 105: 105 ST-R7020, 105 ST-R7025, Tiagra ST-4725, Tiagra ST-4720, GRX Di2 ST-RX815, GRX ST-RX600, GRX ST-RX400