Tesla Gold Series Portable comes in silver alloy case with blue end caps and an alloy switch; featuring a Blue LED. This new multi waveform configuration offers moderate protection from Wi-Fi and general EMF. The Tesla Gold Series Plugin is recommended for homes and offices where EMF is low to moderate. This portable model is for use outside your plugin protected area and is not intended for use inside your home or office full time as it does not offer the same level of protection. The plugin is 6 times stronger than the portable and it is recommended to use a plugin or other large area model wherever possible first and foremost. The portable model is designed for short outings or travel between protected zones in order to keep one balanced and protected without experiencing the shock associated from going from one protected area to another. Most people will experience a detox while initially using this product. This is due to the release of stress on the body from EMF and also boosting of the immune system. A detox maybe a metallic taste in the mouth, thirsty and dry mouth, a mild headache, skin eruptions to name but a few. This is a sign the immune system has gained some ground and has begun to normalize itself. This also tells us the unit is doing its job effectively. It is ideal to drink plenty of water and take some form of vitamin C during this transient time. Once adjusted your body will be acclimatized and no longer detox. Some people don’t experience a detox but notice boundless energy and exceptional emotional stability instead. Tesla Gold Series Portable is not a stand alone unit, and should be used in conjunction with a Plugin model in your home or office or wherever you spend the most time. Ideally a plugin or large area model should be both at your work place and at home, only using the portable when travelling between the protected zones. Tesla Gold Series Portable is great for people who travel a lot in electric trains or who drive electric vehicles. For protecting a large area the Tesla Gold Series Plug-in model or the Tesla Gold Series Cube model would be better. Batteries can be changed by the user very easily, they can also be purchased from us at a very realistic price. Just state the model when ordering and we will provide you with the correct battery. A Torx T-8 (star) screwdriver can be purchased at your local hardware store, be sure to quote the T-8 size appropriate for this model. Most people purchase batteries when ordering first off so as not to be stuck without a working portable. We use disposable lithium batteries as this is the safest option.