What is the difference between low volatility ETF, and a fund of fund MF of the same ETF?

Hi everyone, could you please help me understand the difference between these 2: 1. A low volatility etf 2. A FoF MF of the same etf (99.5% holding is etf)? Is there any difference between these 2 or am I just losing money in expense ratio if I take MF?