s4bill

Is there a trick to removing these wiper blade assembly? I usually depress a tab and pull the arm off the hook. There is no tab. There is large plastic piece surrounding the arm inside and out. Totally stumped on this one. I was considering just replacing the rubber part but do they even still sell them? I bought a pair of Anco winter blade assemblies with the rubber than covers the entire arm but I would return them and just do the refills of the rubber part if that makes more sense. Any help would be greatly appreciated.