In the last trading session, U.S. stocks witnessed a rocky ride given the lingering U.S.-China trade woes. Among the top ETFs, investors saw SPY shed 0.6%, DIA lose 0.4%, and QQQ move 1.2% lower on the day.Two more specialized ETFs are worth noting as both saw trading volume that was far outside of normal. In fact, both these funds experienced volume levels that were more than double their average for the most recent trading session. This could make these ETFs the ones to watch out for in the days ahead to see if this trend of extra-interest continues.QDF: Volume 6.45 Times AverageThis dividend ETF was under the microscope as 583,000 shares moved hands. This compares with average trading volume of roughly 99,000 shares and came as QDF lost 0.6% in the trading session.The move was largely the result of heightened uncertainty and market volatility that are compelling investors to flock to safer avenues and can have a big impact on dividend stocks like what we find in this ETF portfolio. QDF has lost 3% over the past month.SMH: Volume 2.61 Times AverageThis semiconductor ETF was in the spotlight as around 19.5 million shares moved hands compared with average 7 million shares a day. We also saw some price movement as SMH lost 1.9% in the last session.The movement can largely be blamed on escalation in trade tensions that crushed semiconductor stocks as chip makers have significant exposure to China. SMH has lost 10.5% in a month’s time and has a Zacks ETF Rank #2 (Buy) with a High risk outlook.Want key ETF info delivered straight to your inbox?Zacks’ free Fund Newsletter will brief you on top news and analysis, as well as top-performing ETFs, each week. Get it free >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report SPDR Dow Jones Industrial Average ETF (DIA): ETF Research Reports VanEck Vectors Semiconductor ETF (SMH): ETF Research Reports Invesco QQQ (QQQ): ETF Research Reports SPDR S&P 500 ETF (SPY): ETF Research Reports FlexShares Quality Dividend Index Fund (QDF): ETF Research Reports To read this article on Zacks.com click here.