Pardon me if this has been posted and/or is common knowledge, but I have found that some PV setups are slippery enough that tightening/loosening the parts can be a bit of a bother.Using a piece of latex will create plenty of friction to allow you to open most any threaded connection. A few items that can be used are medical gloves, finger cots, even a balloon will work. Finger cots are easy enough to put on but there's really no need to wear the gloves- just a piece cut from a glove will suffice. Just be careful to not over tighten.