Description: LED output indication, the low level LED lights, LED off high Led flashing speed indicates the output frequency variation Produce different frequency square wave or rectangular wave Regulation led flashes can adjust frequency change corresponding to the change Jump choice of different frequency bands outside, RV1 can adjust the frequency adjustment Specification: Size: Approx. 40x20x13mm/1.57x0.79x0.51inch Power supply: Input voltage: 5V-12VDC 5V supply output current: about 10MA 12V supply output current: about 30MA Frequency: 5 bands (Found) J1 file: 0.6Hz ~ 25Hz J2 file: 7Hz ~ 300Hz J3 file: 50Hz ~ 2.5kHz J4 block: 350kHz ~ 6.6kHz J5 block: 6.7kHz ~ 180kHz Adjustable duty cycle range: 0.4-0.99 Package Includes: 1 piece NE555 Signal Generator(10 Pack) Note: Please allow 1-3mm differs due to manual measurement Due to the different display and different light, the picture may not reflect the actual color of the item. Thanks for your understanding