The Klein BLM25 L-Style Ball-End Hex Key is made from top-grade alloy steel that is heat-treated and tempered for added strength and durability. Other features include: Rust and corrosion resistant surfaces. Extra length for hard-to-reach applications. Long side allows easy access, even in restricted or hard-to-reach areas. Short side for higher torque situations and low clearances. Short Arm Length: 15/32-Inch. Long Arm Length: 3-1/4-Inch. Hex Size: 2.5mm. Weight: 0.01-Pound Safety information: Always wear approved eye protection. NOT insulated - will NOT protect against electrical shock. Do NOT use a pipe or similar extension to increase leverage.