Can anyone recommend a good one for use with a rechargeable drill.

Warning if arrested under this act on no account mention you are a caver. In my experience it makes getting you released more difficult you meet the response you are a caver you must be mad

I have done a search and could not find any info,has anyone tried blocking up some of the vents on this drill. I have just stripped ours down to find it full of mud and I am considering blocking off all the vents except for the main fan vent holes. This drill is used in a very muddy cave. Buddy