Hyloc Hydrotechnic Pvt. Ltd. Offers Couplings. Hyloc Hydrotechnic Pvt. Ltd. Is an ISO 9001:2008 and ISO 14001:2004 certified company. The Couplings are available in various sizes from 6mm to 42mm and 6mm to 38mm. The company manufactures tube couplings using steel and stainless steel materials.