This quadrilateral shaped tuning wrench (hammer) can be used for tuning of Guzheng and for most machine devices that have quadrilateral opening. Please measure the tip size of your device before purchasing, make sure size of your device go with the measurement of the wrench quadrilateral. Description: Brand new high quality tuning wrenchUsed for tuning of Guzheng and for most machine devices that have quadrilateral openingThe shaft is made out of steelSturdy and smooth handleSide Length Of The Quadrilateral: Approx. 6.5mmOverall Length: Approx. 16cm / 6.3 inchHandle Length: Approx. 10.5cm / 4.1 inch Package Includes:1 x Square Shape Piano Tuner ToolNote:This quadrilateral shaped tuning wrench (hammer) can be used for tuning of Guzheng and for small machine devices that have quadrilateral opening. Please measure the tip size of your device before purchasing, make sure size of your device go with the measurement of the wrench quadrilateral.