Yes, you can use Sony MBH20 to hear music also.
No. Sony MBH20 do not have volume control button. You cannot increase or decrease call volume but you can use your mobile phone's call volume control button for the same.
No. Sony MBH20 do not have FM radio.
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 any Nokia mobile phone.