Most are implemented by a thin layer of material in the top that slides.The Louis Garneau Hros RTR above has a full layer, but as shown below most road models have nothing in the rear--a frequent impact location--because it interferes with ring fit and stabilizer mechanisms.The level of protection needed would seem to call for downhill helmets, but enduro models may or may not meet the more demanding ASTM F1952 downhill mountain bike racing standard.Extended coverage helmets have become more fashionable this year.MIPS has not yet hit the mass market big box stores where most helmets are sold in the US.Manufacturers are looking at other technologies with similar effects, hoping to mitigate rotational injury, add to the price tag and sell new helmets. Beginning in 2015, Smith had models that use collapsible plastic modules looking like hollow straws in place of foam, but with some standard EPS foam still included in the liner.There are more Conehead designs with dual density impact foam in helmet liners.Conehead helmets have two layers of standard EPS foam.
We still regard MIPS as unproven technology unless you have a helmet that couples so closely to your head that you can't move it even a quarter inch. For the US market the CPSC standard is required by law for any bicycle helmet.Some new developments, including MIPS, we consider unproven.Almost all of the helmets described below meet standards and offer good if not excellent protection.Without comparative test data we usually do not know if a particular model exceeds the requirements of the standard and offers superior protection.Most of them probably do not, even those that provide additional coverage.
Some skate models have full coverage MIPS layers, and a few road models are better than most.