Tickless Human, Baby, Pet, Horse, Hunter, MiteLess Go:You can activate the device by pulling out the plastic tab and then it starts working continously.You have the button to check if the battery is still working. If the light shows up, it's still good. If it doesn't, then you have to replace the product.How to activate videoTickless Mini, Cat:We recommend to charge the device for at  least 4 hours before the first use.For the first activation press the button for 3 seconds and see the LED light in response!How to activate videoTickless Home, MiteLess Home:Once you plug it in the wall it automatically starts working