2. A hearing aid comprises(1) the following special arrangements;(a) a CROS arrangement and its variations (FROS, high-CROS, mini-CROS, focal-CROS and power-CROS);
(b) a BI-CROS arrangement and its variations (BI-FROS, open BI-CROS and multi-CROS);
(2) the options and accessories provided for the Tariff for insured hearing aids and related services (chapter A-29, r. 8) referred to in section 4.
A hearing aid does not include(a) a hearing aid with a maximum sound pressure of over 130 db (20 S.P.L.), except upon presentation of a medical certificate from an otorhinolaryngologist attesting that such a hearing aid is needed;
(b) a hearing aid including any electronic device for eliminating head noise;
(c) a CRIS-CROS and a Uni-CROS arrangement.