These stainless steel heat shields clamp around the neck of the cone filter. They should be angled so that they reflect heat from the engine and when fitted in conjunction with a cold air feed can help circulate cold air into the filter. They will fit cone shaped filters with a neck size from 50mm to 120mm.
There are two options available. In most cases the smaller size (140mm long) is fine, but where the filter is extra large you may want to consider the larger heat shield (220mm long). The neck size fitment range of 50-120mm is the same for both sizes.

NOTE: Air filter not included.