The new improved light had a range of . The optic was designed and built by Chance Brothers and was 'biform' (having two identical lamps and lens arrays, one mounted above the other). Each tier consisted of an eight-wick paraffin burner set within a revolving array of extra large hyperradiant Fresnel lenses (consisting, on each level, of five pairs of lens panels, displaying two white flashes every minute). In clear weather the lower tier alone was used, with its lamp on half power; in limited visibility (as judged by the clarity of the light visible from St Agnes's Lighthouse, away) both tiers were used with the lamps at full power.