https://locksandhandles.co.uk/architectural-ironmongery/door-closers/floor-springs/
Floor Springs - Locks and Handles
floor springslockshandles
https://alephindia.in/isi-product/floor-springs-hydraulically-regulated-for-heavy-doors.php
BIS CERTIFICATION FOR FLOOR SPRINGS (HYDRAULICALLY REGULATED) FOR HEAVY DOORS IS 6315
bis certificationfloorsprings