Acer Leap Ware Fitness Watch - Water-Resistant, Activity Tracker, Heart Rate Monitor with Connected GPS, UV Sensor, 1" Transflective Color Display; Compatible with Bluetooth, Android, iOS - Purple

Q: Os? can i use with tesla apps or alexa?

As mentioned on the product page: "Paired with an Android or iOS smartphone via the Liquid Life app, you can see who is calling or email or texting or messaging and can even play playing music, activate the camera and more - everything is at your fingertips.".

Q: Are the units only in ml and kg? Or can that be changed to US units (i.e. oz and lb)?

Yes you can chance it to it to imperial or metric system from within the app once you install it on your phone.

Q: Se puede contestar la llamada con el acer watch?

While you can see who is calling or texting you, this watch does not offer the ability to answer via the Leap Ware Fitness watch itself.

Q: does this watch have a camera installed?

It does not have a built in camera. "Paired with an Android or iOS smartphone via the Liquid Life app, you can see who is calling or email or texting or messaging and can even play playing music, activate the camera and more - everything is at your fingertips."