Armstron Air Vents

From what I've seen

Armstrong essentially buys their steam vents from others and puts their name on them. So it depends on which model and I'm not familiar with their model numbers. The ones about the size of an old silver dollar aren't bad, but the tall thin ones made in China really won't last.

I've had the best results from Gorton and Hoffman vents. Hoffmans tend to be more expensive for the same capacity.

Before trying to solve a slow or uneven heating problem by changing radiator vents, check to see if your main vents are properly sized and working. Measure the length and diameter of each main and tell us what vent is on it. If your main vents are missing or wrong, installing the right ones will make a world of difference.