Standard input-output norms for optical fibre cable require specified component composition and proof that imports match exported manufacturing inputs. Standard input-output norms specify the bill of materials for a 4 fibre single/multimode armoured optical fibre cable, listing principal inputs such as optical fibre, PBT tubes and masterbatch, thixotropic filling and flooding compounds, HDPE armouring, steel tape, FRP, water blocking tape, hot foil stamping tape, aramid yarn and rip cord, and UV colouring ink. A schedule provides for determination of permissible input proportions for different resultant products and requires applicants to ensure imported goods correspond to the inputs used or required in the declared export product.