Note: The Myo armband is not intended to be worn while plugged in (e.g., while charging the battery) and is specifically designed to be non-operational while plugged in. Please do not wear or attempt to operate the Myo armband while it is plugged in.
It is recommended that the Myo armband be operated within an ambient temperature range of 0⁰C to 35⁰C. This is the standard operating range for lithium-ion batteries, and is commonly applied to many portable electronic devices such as smartphones. As you may have experienced with your smartphone, a Myo armband will, in all likelihood, function perfectly well at ambient temperatures outside of this range; however, Thalmic Labs can and does only warrant the Myo armband for operation within this temperature range.
The Myo armband is designed to be resistant to perspiration and a variety of environmental humidity conditions. However, it is not waterproof. Exposure of the Myo armband to water or excessive amounts of moisture (e.g., sweat) could affect performance. In case of such exposure causing poor performance, allow the Myo armband to dry before further use.
For best performance, maintain a distance of less than about 15m (50ft), and a clear field of view, between your Myo armband and the device with which you are trying to communicate.
To ensure a long life for your Myo armband, avoid using it in environments with significant airborne particulates, such as dust, smoke, salt, dirt, etc.