Can apply for home or travel, for musicians or teachers, or science lovers Deliver clear tone, longer sound and accurate tuning Take with a tuning fork "standard form" is one of the important link in the process of piano tuning. The importance of it lies in the relationship between the sound of a piano and the position of the pitch. Tone temperament order: Determine standard voice The standard pronunciation of each group derived reference tone key tone In reference tone set as the standard sound of the keys is derived for each remaining key tone pitch reference tone group tone keys, each key test the rest of the pitch of the sound Absolute standard A-440Hz tuning fork, sound sensing performance. Soft Case can better protect it from wearing out. Material: steel Size: 4.88*0.79*0.39 inches Weight: 1.17 ounces colour: Silver Package Contents: 1 * tuning fork 1 * bag Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.