While dressing I noticed a neat little detail I hadn't seen before even though I've worn the suit in the past: the belt loops.
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While it looks like a normal belt loop from the outside, there is actually a smaller loop beneath. This small loop is for narrow belts like the one I'm wearing in the photo.
All of the belt loops on this suit have an extra one underneath. The suit is from the late '40s/early '50s and was off-the-rack.
These belt loops are just a sign of quality that we don't see on too many modern suits, especially off-the-rack.