What actually are the Reiki attunements? 

Reiki attunements are acquired from a Reiki Grasp. The Reiki Grasp is channelling/passing Reiki frequencies/vitality into the initiates aura/religious physique to allow them to instantly profit from Reiki themselves at no matter stage the Grasp Reiki trainer has attuned them too. The Reiki Grasp has attuned their frequencies to completely obtain the Reiki vitality.