two metal profiles are connected at a right angle with a stainless steel self-tapping screw with a drill close-up. assembling the

metal profile frame structure partition wall fastening assembly construction light layout work selftapping screws universal building materials stiffeners monolithic drywall empty reinforced aerated concrete gas block brick floor corner two profiles are connected right angle stainless steel self-tapping screw drill close-up assembling for from close-up profile