Amazon workers have held an increased number of protests over the last year, which is one sign that momentum to organize has picked up among some of its 650,000 worldwide employees. But unionizing efforts so far have not succeeded. Amazon increased minimum wage to $15 an hour last year and offers generous benefits. It's also fending off unions using tweets, training videos and internal hires. Watch the video to learn what unions are all about and how they could impact Amazon and its workers. *** Correction *** This video incorrectly refers to Amazon's spokesperson as Rachael Lightly. Her name is Rachael Lighty. Three big unions that are talking to Amazon workers are the Teamsters, the United Food & Commercial Workers Union, and the Retail, Wholesale and Department Store Union, among others. Recent worker protests point to organizing efforts. On Amazon Prime Day in July, a handful of Amazon workers at a fulfillment center in Shakopee, Minnesota, went on strike. It was the first strike by U.S. workers during the company's annual sales events that started five years ago, and one of several protests that's taken place in the U.S. in the past year. Throughout Amazon's 25-year history, there have been multiple rumblings of workers trying to unionize. So far, none of the efforts have been successful. With record-breaking sales numbers and newly doubled shipping speeds, however, momentum to organize has picked up among some of Amazon's more than 650,000 worldwide employees. Efforts to curb union activity inside Amazon include a leaked training video that was sent to Whole Foods managers in 2018. In it, an animated man wearing a yellow safety vest says, "We are not anti-union, but we are not neutral either. We do not believe unions are in the best interest of our customers or shareholders or most importantly, our associates." It goes on to give tips to managers for spotting union activity. "Make it a point to regularly talk to associates in the break room. This will help protect you from accusations that you were only in the break room to spy on pro union associates." Amazon notes the training video has not been used since last year and says it was in compliance with the National Labor Relations Act. » Subscribe to CNBC: https://cnb.cx/SubscribeCNBC » Subscribe to CNBC TV: https://cnb.cx/SubscribeCNBCtelevision » Subscribe to CNBC Classic: https://cnb.cx/SubscribeCNBCclassic About CNBC: From 'Wall Street' to 'Main Street' to award winning original documentaries and Reality TV series, CNBC has you covered. Experience special sneak peeks of your favorite shows, exclusive video and more. Connect with CNBC News Online Get the latest news: https://www.cnbc.com/ Follow CNBC on LinkedIn: https://cnb.cx/LinkedInCNBC Follow CNBC News on Facebook: https://cnb.cx/LikeCNBC Follow CNBC News on Twitter: https://cnb.cx/FollowCNBC Follow CNBC News on Instagram: https://cnb.cx/InstagramCNBC #CNBC #Amazon How Amazon Fends Off Unions