All active therapeutic devices intended to administer or exchange energy are classified as class IIa unless their characteristics are such that they may administer energy to or exchange energy with the human body in a potentially hazardous way, taking account of the nature, the density and site of application of the energy, in which case they are classified as class IIb.
Tá na feistí teiripeacha gníomhacha ar fad a beartaíodh chun fuinneamh a thabhairt nó a mhalartú aicmithe mar aicme IIa seachas má tá saintréithe acu lenar féidir fuinneamh a thabhairt nó a mhalartú chuig corp an duine nó uaidh ar bhealach a d'fhéadfadh a bheith guaiseach, agus cineál, dlús agus láthair fhorchur an fhuinnimh á gcur san áireamh, agus sa chás sin tá siad aicmithe mar aicme IIb.