This one isn't at all like a wagtail, it does have a swivel joint and is a useful, if heavy [ish] tool.
The wagtail is the bee's knees, the one I use is the flipper and wouldn't go back to an applicator and separate squeegee for all the tea in China.
Once you've mastered the technique of using it, it is miles faster and more efficient than using 2 separate tools.
It's less messy with regards to excess water too, is the ideal tool to use with a pole, especially on shop fronts etc.
Although due to its design, it can often mean you need to spend a little more time on detailing.
The Wagtail isn't cheap...although to look at it, it sure as hell looks cheap and flimsy, but it's worth every penny.
If you are a carpel tunnel sufferer, try to use your fingers more to rotate the wagtail, I've let other window cleaners have a go with mine and noticed they use their wrists to rotate the wagtail as they would a normal squeegee, which actually made them look extremely awkward.
I've always kind of assumed that a wagtail user would instinctively adapt their technique to swivel the wagtail more with the fingers as they got the hang of it, but perhaps that isn't always the case??
Ian