Concertinas are awesome. It allows packing glider regardless the space or wind in less then 2 minutes. Finding a suitable one took me few tries but it was worth it.
My requirements: light, packable, durable, possible to leave packed glider connected to harness, zipper from trailing to leading edge.
First I tested Gradient concertina but I was unable to pack it into my harness (Supair Delight 1) because of nonremovable foam on leading edge was too big. Sad.
Karpofly concertina I liked. Well packable, zipper to leading edge and holes on both top (imho useless) and bottom. It served me well for a long time. I had just minor quality issues: zipper paw was broken soon, attaching a small cord instead made it better than original. The buckles attachment if tighted too much it was difficult to loose them again as they stucked. It was visible overstressing the material where buckles were attached but after a 2 years of intensive usage no issues. When packing, sometimes the glider stucked into zipper if not careful and last, finding buckles when wing lays on top can be slightly challenging as they are connected near the middle. I used pocket for risers few times, looks strange but do its job. The instructions how to pack it was confusing, I found my own way. Generally a simple but good product.
UP concertina first I hated, but it was fine after few days. It is greatly packable, even to smaller blob than Karpofly. I loved buckles on edge so it was very easy to find them bellow glider. I do not like zipper from leading edge but it was at least possible to leave glider connected to the harness, and when glider was well deflated, it was fine. The lines or glider has bigger tendency to stuck into zipper than in others. I did not use pocket for risers. Buckles for holding concertina packed was too complicated for me, I have never successfully passed this test. Generally a nice and well usable concertina.
Advance concertina I saw just briefly. Looks very nice but there is no hole in trailing edge and when you want leaving harness connected, you need to lead lines through leading edge. Surprising imperfection from Advance, I knew it is therefore not for me.
Gingliders concertina I loved from beginning as attention to details is obvious. Material is light, perfectly packable into a tiny blob but also seems very durable. Zipper can be moved in both directions and there is a small hole on trailing edge side, leaving harness attached is easy but also a pocket for risers is better solved than in others. Stucking the glider or lines into zipper is almost impossible as there is a protection cover, and working great. Maybe only the buckles connection could start even more near sides like UP. The downside is higher price, at least in my country. Also a line holding concertina packed is separate. No issue for me but if someone wants to transport just glider in concertina, he will want to search for it. IMHO a top product nowdays, I have also seen a picture with Chrigel using very similar concertina.
It took a while to find the right concertina for me and it is interesting how many aspects can this simple piece of cloth can have. But as packing/unpacking is every flying day, and I do not enjoy this part, anything making it faster and easier is worth some investment.
Nowdays there are probably newer and improved models on market 🙂 Check it!