My Milwaukee PH55 pro test pen came with a rubber and hard cap. The rubber doesn't fit on underneath the hard plastic cap. Is there a specific difference in purpose between the two caps or one I should be leaving on? I've been using the soft rubber on because it says to store it with a tiny bit off the storage soloution and it seems like the hard plastic one would require quite a bit.
![PXL_20211231_022633606.jpg PXL_20211231_022633606.jpg](https://www.reef2reef.com/data/attachments/2411/2411076-e04975141c3f9755763363da8f150b0f.jpg)
![PXL_20211231_022633606.jpg PXL_20211231_022633606.jpg](https://www.reef2reef.com/data/attachments/2411/2411076-e04975141c3f9755763363da8f150b0f.jpg)