Sony NS-WS623 is quite light weight. It weighs just about 32 grams.
Sony WS623 has 4GB internal memory and you can further expand it up to 16GB with the help of MicroSD card.
No. Sony NS-WS623 does not have FM radio.
You can check the charging status with the lamp ( 3 ).
While the battery is charging: orange when charging is complete: green