Root wrapping in containers is a serious problem. In some cases, wrapped roots can actually kill plants. Root-tip-trapping is another non-chemical method of pruning roots. The RootTrapper II works by utilizing a unique fabric; much like using velcro on the root tips. When the root tip grows into the fabric it gets stuck (or trapped) at which point the root is forced to branch. These bags can prune up to 100 root tips in just 1 square inch of fabric! The white lining not only makes these bags much more durable, but it also reflects heat keeping root systems cool. RootTrapper II containers are perfect for pruning roots in hydroponic systems utilizing media like perlite or hydroton (clay pebbles) due to the fact that these containers do not air prune the roots. Because irrigation is so frequent in indoor hydroponic systems, air pruning is not possible; therefore the use of RootTrapper II containers will help create healthy fibrous root systems.