Sony MBH20 has 10 meters range.
Yes, you can use Sony MBH20 with Gionee A1 easily.
Sony MBH20 has average talk time of up to 8 hours. So, you can use it for almost 2 days talk time.
Yes, you can use Sony MBH20 with micromax mobile phone.
No. You cannot change the battery of Sony MBH20. Sony MBH20 comes with in-built battery.