In my case, "light" duty meant they bent within the first 20 minutes.  I used them on a green tree branch of approximately max width (4-5/8") and the blades separated sideways causing the pruner to twist in my hand.  This force caused the back bar (ie: not the sharp blade but the piece it cuts against) to bend outward.  I used a rock to press against and bend it back to continue cutting more branches but this happened a couple times and I gave up.  If your 'light' duty means you'll only ever cut fairly soft and small things, these may work for you.  But I doubt it.  Eventually, your're going to attempt something stiff and they're going to bend.