10th February 2016 O = Oval Oval shaped pillar boxes have been a feature of three different designs of pillar box. The large dual aperture Type C boxes designed to separate mail at the time of posting; and also the Type D and Type E boxes, made in 1931, which had a single aperture at one end and a stamp vending machine at the other. The Letter Box Study Group 2016-02-10T16:19:21+00:00 Oval shaped pillar boxes have been a feature of three different designs of pillar box. The large dual aperture Type C boxes designed to separate mail at the time of posting; and also the Type D and Type E boxes, made in 1931, which had a single aperture at one end and a stamp vending machine at the other. https://lbsg.org/testimonials/o-oval/