Unique necklace design and Build-in 8G memory, 40 hours battery life when fully charged, 90 hours maximum capacity. Great for conference,letcture, investigation, evidence collection.Having only 1 buttons, this voice recorder can be used by less experienced users. Just push it down to the usb port side , you will see a red led on and then blue led blink 5 times and off, it is recording now. push it to another side, you have switch off the device. there is no visible led/light during recording.Please charge it if you have not seen the led indicator after turn on the device.)How to play: The device comes without earphone. one need to connect it to the computer to play. Please turn off the recorder before connecting to the computer usb 2.0 port. Otherwise you can not connect it successfully.It is both PC and Mac USB 2.0 Compatible. Please don't buy it if your computer have not USB 2.0 port.Dimensions (60mm*32mm*18.6mm)- Conveniently fits in any pocket or purse for easy access and portability.Time setting: Please connect the recorder to your computer USB 2.0 Port and create a "txt" file UNDER THE FOLDER RECORD, then save it. The format and the content of the file should include the date and time. please make sure the "year" must be four digits and the others be two digits. such as 20170101103030(it means in Jan.1st 2017 at 10:30'30'')