... Grade: 4.6,4.8,5.6,5.8,6.8,8.8,10.9,12.9 ( General and High strength) >> Surface treatment: plain, black, zinc, electro galvanize, hot dipgalvanization ... License from the Ministry of Railways, P.R.China. 2.From 2006, we have manufactured the products of high speed ... , Malaysia and Africa and so on. Pictures: 1. Certificate: 2. Various honorary certificates: 3. Product: Different types of twist spikes ...