Technical Diving - TDI Intro To Tech, Basic 5, 인트로 투 텍, 베이직 스킬 by 브라더스쿠바 

There are various ways of doing skills. Such skill as S-drill can be more flexible than other skills. However, what we must know is ‘WHY’ we practice those skills in that particular way
스쿠버 다이빙의 '바른 지식'을 전합니다
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