The OM (OHM) forks are tuned at the frequency the Earth rotates around the Sun in a year. It is known by many in the sound healing world as "The Master Tuning Fork." It is a "must have" for anyone wanting to delve into the fascinating and wonderful world of sound therapy. We offer the Low OM 68.05 Hz in the weighted version, the Mid OM 136.10 Hz in both the weighted and unweighted version, and the High OM 272.20 Hz in both the weighted and unweighted version. These forks are great for clearing, grounding, relaxation, meditation, body work, acupressure and etc.This is a must have for anyone wanting to explore sound therapy. We also offer the OM set which is the Low, Mid and High OM in the weighted version. - SozoSoundz.