The cast epoxy resin head-form is best suited for use in the tests specified in 10.2.The all aluminium head-form is best suited for use in the tests specified in 12.1, clause 13 and clause 14.For the tests specified in 3.2 and 9 the polyurethane covered head-form only shall be used.Other head-forms may be used if known or demonstrated to give equivalent results.