Where can I find On Balance Volume for bitcoin? (or ETH, LTC?) I recently read about the usefulness of On balance Volume (OBV) in predicting price movement. 

I use GDAX and don't think it has OBV. 
(Or is there?)

Any exchange that displays OBV?

Thanks.
No GDAX don't offer OBV.

However, you can use www.tradingview.com and apply OBV on chart from for example Coinbase/GDAX or other exchanges.

The sign-up is free, you only have to pay if you want to use more advanced technical analysis methods.

How it looks like: