Based on available information, Polarna Ebike appears to be a legitimate product. It has been reviewed by customers on Amazon and other platforms. The Polarna M4 Electric Bike is described as a fast and fun off-roader that folds for easy transport. It's also noted for its full-suspension and fat-tire features. However, some customers have reported reliability issues and concerns about customer service. It's always recommended to do thorough research and read multiple reviews before making a purchase.