Slack, Uber and Airbnb are among the hottest companies readying a listing this year.

All that activity from so-called tech unicorns — private start-ups with valuations of more than $1 billion — is setting up for what could be a record $100 billion year in initial public offerings.

For the investor looking for exposure to the red-hot IPO market, CFRA senior director Todd Rosenbluth has a way to play it: Renaissance Capital's U.S. IPO ETF.

"You get Altice, you get Snap, you get Spotify," Rosenbluth told CNBC's "ETF Edge" on Monday. "What's also intriguing about this ETF besides being very small and not that liquid is that it rebalances every quarter and then a stock can only be inside for two years so you get a short window of time to hold these potential up and coming companies."

The IPO ETF has far outpaced the rest of the market this year. It has rallied 20 percent, more than double the advance on the S&P 500, and has bounced nearly 30 percent off its Christmas Eve lows. Its largest holdings include Vici Properties, Altice and Invitation Homes.

However, the relatively short time frame before a stock is rotated out of the IPO ETF means investors might be shut out of potential growth, Astoria Portfolio Advisors CIO John Davi says.

"There's another competing product, FPX, which holds onto stocks for four years," Davi said on "ETF Edge" on Monday. "The argument could be that it takes longer for you to monetize your IP. So if you think about Facebook, when they IPOed, it took them many, many years for them to actually become profitable and for the stock to accelerate."

The First Trust U.S. equity opportunities ETF (FPX) tracks the IPOX 100 U.S. index, a collection of the 100 biggest and best U.S. IPOs. Its largest holding, PayPal, debuted in mid-2015 and has a nearly 11 percent weighting.