The Park Tool ST-3 Three-Way Socket Wrench is a classic, professional-grade bicycle workshop Y-wrench designed to handle smaller common fasteners. It combines the three most widely used hex-nut socket sizes found on traditional, modern, and electric bicycles—8mm, 9mm, and 10mm—into a single, highly durable hand tool.

Technical Specifications & Design

• Socket Materials: Made from forged, heat-treated Chrome Vanadium (Cr-V) steel that has been hardened and chrome-plated for outstanding durability and rust resistance.
• Deep-Wall Sockets: Precision-machined, thin-walled metric sockets ensure the tool can cleanly reach inside recessed component areas without binding up.
• Iconic Y-Body Ergonomics: Built with Park Tool’s classic three-pointed design wrapped in a molded, glass fiber-reinforced composite center body. This shape fits naturally in the palm of your hand, offering maximum manual leverage and allowing you to spin the tool rapidly using two hands.
• Primary Applications: Indispensable for adjusting traditional rim brake caliper nuts, brake pad hardware, accessory racks, fender mounts, and components on certain e-bike battery brackets.