Many physical entry technicians make highly effective use of the Under Door Tool device. Some covert entry experts with extensive field experience will even opt to customize their Under Door Tools. One of the most popular modifications has proven to be the use of retractable line systems to help manage the string both during storage and while the Under Door Tool is in use. The NotSoCivil Engineer has a video on his YouTube channel showing such a practice... https://www.youtube.com/watch?v=5y4kNsS38F0
While the use of a retail device such as the KeyBack product (seen in that video) can be effective, we have found a source for an even smaller and -- perhaps more importantly -- quieter line management solution.
This Silent Retract Line is an over five foot length of heavy-duty cord engineered to operate exceedingly quietly. Extension and retraction is quick and efficient, and the addition of a rubber buffer means that not only is the operation smooth but even letting the unit go and allowing it to retract completely on its own is unlikely to result in any loud snapping sounds.
Given how frustrating the stock included wire-style line of a conventional Under Door Tool can be, this unit is a helpful and professional upgrade that many choose to make to their field equipment.