Penko Fishing Fish Rulers Decals (2 Pack) Adhesive 38” Transparent Ruler. Fish ruler decal allow fisherman to measure their fish quickly and accurately before putting your catch on your vessel.The Fishrule ruler is a 1/4" x 38” clear decal you apply directly onto your speargun, Polespear or Fishing Rod.This self-adhesive vinyl decal applies easily and allows the color of the fishing rod to show through with only the 1/4" white increment marks visible.Guide tested, this flexible material easily conforms to the curves of your speargun, polespear or fishing rod and will not affect the action.Each 38” long Fish ruler can be cut to your desired length.