A:AnswerNo you will have to buy the hub. If you purchase the starter kit that comes with the hub and 2 bulbs that is all you will need. You can control up to 64 bulbs on one hub
A:AnswerZigbee. The wireless versions will clearly state wireless on the packaging and will have the universal wifi icon stamped on them. They work directly off your router and have proven to not be as reliable as the zigbee bulbs requiring the hub. I recommend getting the hub because of its direct ethernet to the router/modem.
A:AnswerIf you're asking whether this bulb supports 5ghz wifi then the answer is no. But that's because this is not a wifi bulb. It's a Zigbee bulb that requires a hub, such as the Smartthings hub (which is how I use these).
A:AnswerYes, it is dimmable. We have several of these, using them with a Smartthings hub (a hub is required) along with both Alexa and Google Home devices. They work well.
A:AnswerSome of these bulbs require a hub to work and some don't. Check the "Overview" section before purchasing. The "Smart Wi-Fi" ones look like they don't need the hub but READ THE OVERVIEW to be sure. I needed ones that work with a hub and almost purchased the wrong ones.