WA-DI-CO letter scale

This stationery products WA-DI-CO letter scale has the addition "PENNYWEIGHT". It's propably a product of Triner, on which WA-DI-CO added it's own name sticker and rate chart. This cardboard rate chart also has the description: wadico pennyweight postal scale. This specimen came from Canada. The rate chart is Canadian orientated. As yet this hinders a correct dating. This letter scale exists in different colors. The range is 2 Lbs. The rates for mail to Canada, USA and the British Empire stand beside the Air Mail rate and the local rate. Also rates for books + circulars and for newspapers are given. This letter scale is a spring balance. This spring is hided behind the housing. With a little wheel this letter scale can be tuned to zero.