Color: Red, Simple Construction , design, easy to install and debug. Designed to measure the frequency of oscillation of most crystal oscillators. Based on PIC minicontroller can measure the frequency of 1 Hz to 50 MHz. digits of precision, for example kHz x.xxxx, MHz or .xxx x.xxxx MHz. General for feeding USB interface can be used for power supply, AC adapter or a battery of 9 V can be used too, it is used. Optional mode of power saving: can automatically convert the display if the frequency does not change significantly in 15 seconds small number of components: a PIC16F628, 5, 7-segment LED screens, a 20 MHz crystal and some resistors Material: PCB;. Frequency range: 1 Hz-50 MHz Glass Test Range: 4 KHz-48 KHz Built Item Size: 8 * 5.5 * 0.7 cm / 3.2 * 2.2 * 0.3 inches Package Contents: 1 * Frequency Counter Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.