As materials stocks build on their gains, one investing professional is getting even more constructive on the space.

Witnessing the 4% pop this week in the Materials Select Sector SPDR Fund, a market-cap-weighted index that counts the stocks of Linde and DowDuPont among its top holdings, CFRA's Todd Rosenbluth says investors should consider buying into this economically sensitive space.

"We're positive on a number of these stocks that are in XLB," Rosenbluth, who runs ETF and mutual fund research at his firm, told CNBC's "ETF Edge" on Monday. "This is ... a concentrated portfolio — 70% is within the top 10 holdings — but we at CFRA have strong buy or buy recommendations on many of them."

That includes names such as DowDuPont and Freeport McMoRan, two companies that Rosenbluth said were "dominating" in their respective markets, chemicals and mining.

"We think this is a good way to play the materials theme," he said. "I think investors are comfortable taking risk on with the Fed on pause where they are, [with] global economies doing well enough. I think investors are comfortable taking on a more cyclical slant."

But when it comes to determining the best ETF investments in the materials space, Astoria Portfolio Advisors founder and chief investment officer John Davi said it depends on investors' risk appetites.

"They're both performing in line year to date," he said of the Materials Select Sector SPDR Fund and its smaller, equal-weighted counterpart, the Invesco S&P 500 Equal Weight Materials ETF.

"If you want more risk in a portfolio, you buy XLB, market-cap weighted," Davi said, also on "ETF Edge." "If you want less risk contribution by each stock, then the equal weight is fine, from our perspective."

The Materials Select Sector SPDR Fund is up over 14 percent year to date, outperforming the Dow Jones Industrial Average so far in 2019.