WaveCel is a rotational impact protection system used exclusively in Bontrager ski helmets. It features a collapsible cellular structure inside the helmet that flexes, crumples, and glides on impact to absorb both rotational and linear forces — the kind you'd experience in a real-world fall where you hit the snow at an angle.
According to Bontrager's testing, WaveCel can be significantly more effective than MIPS at reducing concussion risk. While MIPS uses a low-friction sliding layer that allows your head to slip slightly on impact, WaveCel actively crushes to absorb energy, tackling the same problem with a different approach.
The trade-off is that WaveCel adds a bit more weight than MIPS, and your options are limited to Bontrager models. Both systems are solid choices — the key takeaway is that having either one is far better than a helmet with no rotational protection at all.