According to market-research firm NPD Group, the NES Classic sold more units in June than any other gaming hardware platform. It outsold the Xbox One, PlayStation 4, and the Nintendo Switch, although the PlayStation 4 led the market in terms of dollars sales.

“This is the first time a Nintendo Entertainment System console has led in monthly unit sales since NPD tracking began in 1995,” NPD analyst Mat Piscatella said in a tweet. That feat is all the more impressive given that the NES Classic was available for sale only for the last two days of the month.

US NPD HW – The NES Classic was June 2018's highest unit-selling hardware platform, while the PlayStation 4 led the market in dollar sales. This is the first time a Nintendo Entertainment System console has led in monthly unit sales since NPD tracking began in 1995.

— Mat Piscatella (@MatPiscatella) August 1, 2018

NES stands for “Nintendo Entertainment System,” the iconic 8-bit video game console first released in the mid-1980s. The NES Classic retails for $59.99 and comes loaded with 30 games including Super Mario Bros., Metroid, Donkey Kong, The Legend of Zelda, and Pac-Man.

In November 2016, Nintendo began selling the NES Classic as a limited-edition replica of the original NES introduced in 1983. Over the next six months, Nintendo sold more than 2 million of the devices.

Demand for the NES Classic was so strong that third-party sellers unloaded the console for nearly three times its regular $60 retail price last year. In May, Nintendo said it would relaunch the NES Classic on June 29. In that short time, it became a hot seller.

Part of the appeal of the NES Classic is its price tag, which is far less than the $300-$400 for Playstation 4s. If Nintendo has been leaving money on the table, investors haven’t seemed to mind. Nintendo’s stock has gone up 74% in the past two years, more than double the 33% rise in the Nikkei 225 in that time period.