I tried hardly pushing in strongly at the preparedness that it can break like answer in the case that the inner diameter is not small. At first it did not work, I left it in the scorching sun, softened and stretched out and I entered it, so I entered it.
When checking outdoor electrical equipment
On 2016-06-02 21:15:42
The inner diameter is small and it does not enter the helmet. I did not enter my colleague 's helmet. I do not think that it was commercialized assuming a general helmet. It will not be used.