The Robo-Stox Global Robotics & Automation Index ETF (NasdaqGM: ROBO), criticized as too much of a niche idea to prove popular with investors when it debuted in late October, is proving the critics wrong.

Tuesday’s announcement that ROBO has surpassed $100 million in assets under management proves as much. Apparently, some investors like the idea of a dedicated robotics ETF because ROBO has amassed $102.3 million in assets in less than six months of trading, according to Robo-Stox data.

As of Feb. 5, ROBO’s AUM total was north of $79.1 million, according to issuer data. ROBO has been highlighted as a way of gaining access to previously high-flying 3D printing stocks, but some of those names have been a drag on the ETF this year as the fund is down 4%. [Robotics ETF Holds Some 3D Printing Stocks]

“The robotics and automation sector has reached a tipping point, with robots simultaneously becoming more sophisticated and less expensive to integrate,” said Rob Wilson, Chief Executive Officer of Robo-Stox, said in a statement. “Our exchange-traded fund gives investors an opportunity to benefit from the continued expansion of producers and suppliers within this dynamic and growing industry.”

Although ROBO is pricy by the standards of traditional, non-leveraged ETFs with an annual expense ratio of 0.95%, the ETF has climbed more than 10% since its Oct. 22 debut, beating the S&P 500 by nearly 300 basis points over the same time.

Additionally, the once-far flung concept of robotics is gaining some momentum. For example, the International Federation of Robotics expects that worldwide sales of robots will rise by 6 percent between 2014 and 2016, and over 190,000 industrial robots will be supplied to companies around the globe in 2016, said Robo-Stox in the statement.