Abstract: A protective shock absorbing element block made of rigid and brittle foam is provided with superficial or internal structure irregularities (20), having sharp edges in the foam to enable its immediate crushing by cracks propagating in depth throughout its entire volume, which facilitates its fragmentation with predicted characteristics. As a variant, a superficial hardening coating (28) could be used, to fill in the outer pores (27) in the foam, together with a lateral clearance with the envelope, or studs covering the inside of the envelope. Applies to shock resistant protective shock absorbing elements, particularly covering packagings exposed to drops.