... .0,master and slave mode 2.Ultra low current consumption MDCS71 Class2 Bluetooth Low Energy 4.0 Single Mode ModuleDescription ... go)* Proximity sensors* HID keyboards and mice* AutomotiveFront Side of MDCS71 bluetooth low energy V4.0 module,dimensions: 19.15mmx12.04mmx2 ... .45mmBack Side of MDCS71 bluetooth low energy V4.0 module,dimensions: 19.15mmx12.04mmx2 ...