He hua o te pepa piauau wera, konumohe wera pereti zinc whakakikoruatia, pepa electrogalvanized, me etahi atu, i muri i te maimoatanga o te mata (te whakaheke matū me te maimoatanga huringa matū), ka pania ki te paparanga, ki te maha ranei o nga papa o te paninga waro i runga i te mata, a ka tunua ka rongoatia.He marama te taumaha, he ahua ataahua me te pai o te aukati waikura, ka taea te tukatuka tika.