▁by ▁acting ▁as ▁a ▁distributed ▁B rag g ▁reflect or . ▁A ▁well - des igned ▁die lect ric ▁co ating ▁can ▁provide ▁a ▁reflect ivity ▁of ▁more ▁than ▁ 9 9 % ▁across ▁the ▁visible ▁light ▁spectrum . ▁This ▁reflect ivity ▁is ▁much ▁improved ▁compared ▁to ▁either ▁an ▁al umin ium ▁mirror ▁co ating ▁( 8 7 % ▁to ▁ 9 3 %) ▁or ▁silver ▁mirror ▁co ating ▁( 9 5 % ▁to ▁ 9 8 %). ▁ ▁Por ro ▁pr ism ▁bin oc ular s ▁and ▁roof ▁pr ism ▁bin oc ular s ▁using ▁the ▁Ab be – K o enig ▁roof ▁pr ism ▁do ▁not ▁use ▁die lect ric ▁coat ings ▁because ▁these ▁pr isms ▁reflect ▁with ▁very ▁high ▁reflect ivity ▁using ▁total ▁internal ▁reflection ▁in ▁the ▁pr ism ▁rather ▁than ▁requiring ▁a ▁mirror ▁co ating . ▁ ▁Term s ▁used ▁to ▁describe ▁coat ings ▁ ▁For ▁all ▁bin oc ular s ▁ ▁The ▁presence ▁of ▁any ▁coat ings ▁is ▁typically ▁denoted ▁on ▁bin oc ular s ▁by ▁the ▁following ▁terms : ▁▁ ▁co ated ▁opt ics : ▁one ▁or ▁more ▁surfaces ▁are ▁anti - reflect ive ▁co ated ▁with ▁a ▁single - layer ▁co ating . ▁ ▁fully ▁co ated : ▁all ▁air - to - glass ▁surfaces ▁are ▁anti - reflect ive ▁co ated ▁with ▁a ▁single - layer ▁co ating . ▁Pl astic ▁l enses , ▁however , ▁if ▁used , ▁may ▁not ▁be ▁co ated . ▁ ▁multi - co ated : ▁one ▁or ▁more ▁surfaces