EFR training ! You can only learn it right when you try out it yourself! ?? For any kind of inquiries, feel free to contact us at -E-mail : gooddiverkorea@gmail.com -Web : www.gooddiver.com -Tripadvisor : Good Diver -Instagram : yun_gooddiver -Youtube : https://www.youtube.com/channel/UCIFYCGgqKmdeNvhtXzJUkHQ