Don’t expect to see Warren Buffett sharing a joint with Willie Nelson any time soon, but the legendary investor doesn't seem to mind making some money in the legal pot industry.

A Wisconsin-based subsidiary of Buffett’s Berkshire Hathaway is marketing its freestanding structures to over a thousand pot dispensaries in Colorado and Washington state, where recreational marijuana use is legal, to expand their growing space. Cubic Designs Inc. sent out fliers, offering to help “grow your profits” by adding on extra space to growers’ warehouses and allowing them to increase the number of plants they cultivate, reports Bloomberg News.

Several growers have contacted Cubic Designs on their own in recent months, asking about its “mezzanine systems” that would expand their space to grow crops.

It’s a savvy business move since the legal pot industry is booming – with sales expected to hit $8 billion a year in 2018. In addition to Colorado and Washington and 20 other states with legal medical marijuana, about a dozen other states are expected to legalize pot in the next few years.