Two-way zip essential?

The two-way zip seems to be increasingly rare these days and only present on more technical (and more expensive) apparel. Are there any pieces that you strongly prefer have a two-way zip? Shells? Insulating layer? Wind layer?

Any layer that goes on and off over a harness.

csproul wrote:Any layer that goes on and off over a harness.

I find the second slider really useful on technical shells but for most activities, insulating layers are typically short enough to be OK with a one-way zipper. These days, the main use I have for the second slider is for taking a leak but I do find it extremely useful for that, with or without a harness over the jacket.

The switch from two-way to one-way zippers on technical shells happened when the water-resistant zippers started appearing. One-way WR zippers were installed even on technical and expensive jackets despite the fact that two-way versions were available. The switch to jackets without low pockets and with a short and narrow cut in the lower half for wearing under a harness or hip belt had happened some years previously. Just speculation on my part but perhaps the manufacturers felt that the two sliders were no longer necessary for this type of jacket design. They may have kept using them on non-WR zippers because people still expected their technical jackets to come with two-way zippers. Then when they made the switch to water-resistant zippers, they may have taken the opportunity to do away with the second slider. Whatever the reason, I disagree with it.

Unrelated to climbing (or to taking a leak), I’ve also found two-way zippers very useful for all jackets (shell and insulation) that will be used to zip with home-made pregnancy / babywearing shell and fleece inserts. In my web instructions, I suggest actually removing the one-way zipper from the fleece jacket of a jacket-and-insert system and replacing it with a two-way zipper compatible with that of the fleece insert. That’s what I did with the fleece jacket that became the model for the instructions and patterns and I was really glad that I did.