FEATURES: WIRELESS BLUETOOTH COMMUNICATION allows you to interface with most Castle Link compatible ESCs and accessories to change parameters and update firmware. COMPACT AND LIGHTWEIGHT at 1.20" x .81" x .25" (30.48mm x 20.55mm x 6.55mm) and 0.23oz (6.62g), it can be installed in the vehicle or airframe without significantly increasing model weight. CONVENIENT WATERPROOF DESIGN allows you to quickly adjust settings in the field without disconnecting or disassembling the model. It can stay installed in the model or be easily swapped between models. FREE APP DOWNLOAD is readily available in the Apple App Store. Once downloaded it does not require a data connection so it can be used in the most remote of areas and won’t use data. EASY TO USE application can be used with multiple B-Link Bluetooth Adapters or can store model information and allow you to use one adapter on multiple models. PASSCODE PROTECTED with (user-selectable) 4-digit code to prevent unwanted tampering with your settings. SYNC information between multiple iOS devices by creating a free account (requires internet connection to sync database).