We are the INSI Company, a large holding specialised in prefab steel house production. We are now interested in the following products to be used for our houses: bolts M 20x50 (40.000 Pcs), which are inaccordance with DIN 933, GOST 7798, - bolts M 20x60 -(50.000 pcs). - screws M20 -(190.000 pcs) - DIN 934 or GOST 5915-70 -nuts M 20-(80.000 pcs.)-DIN 125 or GOST 11379-68- bolts 12*40 with screws and nutsMaterial Class 5.8 (steel strength)Could you please provide a quotation and detailed specification of these productsDo you have certificates that your products correspond to DIN or other standards?We hope for long term and serious cooperation