multi-directional dual roller trackfor pipe&joint system. Material:Iron track+ PE roller Length:4 meters per piece SPECIFICATION: U channel : aluminium alloy Rollers: diameter 34mm (Black) Fitting: JY series connectors U channel : steel sheet (galvanized) Rollers: diameter 34mm (White) Fitting: JY series connectors How to calculate the length of roller track The standard gradient is 6% ( 3.5°) , so to measure a track in relation to its overall length , the calculation is follows: The length of the roller track equivalent to the overall length-65mm Margin: the maximum margin must be less than 5mm divided between the two ends. HOW TO CACULATE THE LENGTH OF CENTER AND EDGE GUIDES The length of a GL edge guide is that of the roller track minus 100 mm. The length of a GC center guide is identical to that of the roller track TIPS: 1 Cuting tracks too short weakens the whole level of the rack . Avoid using tracks whose length is different to that of the internal dimension of the level. 2 Protruding tracks may make a risk of injury when assembled incorrectly . 3 The correct way of assembling a roller track must obey blows: The maximum margin between the connector end-stop and the rail is 5 mm. Remember the standard gradient is 6% Track length=overall length-65mm