Join OPC Volume Challange on coinsmarkets. https://coinsmarkets.com/news.php

Trade OPC as much as possible till the end of the year. For the best 5 traders we have free OPC! Free OPC will be credited in wallet in New Year.
Prizes:
1st - 10000 OPC
2nd-5000 OPC
3th-2500 OPC
4th-1500 OPC
5th-1000 OPC