Lumia 640 xl is work on windows operting system and sound reception is also good this phone is vary easy to use . I was use those phone at 2 years good look from lumia and power ful camera perfomance besacuse back side camera with ZEISS lens 13 MP and front camera 5 MP back camera with yellow flesh light. Range of features is low but generan users for that ok. and this phone reselling value is vary low so I suggest to buy this phone for genaral users this phone is not hangging.