Everyone knows that plastics can be significantly lighter than their metal counterparts. But, even plastics can vary greatly in their weight. The Pentagon has been experimenting with polyethylene — a much lighter alternative to Kevlar, which has been used traditionally as of late. This article, originally published by Plastics News (April 6, 2016) highlights the potential impact on US troops, whose loads are about to get 23% lighter: http://www.plasticsnews.com/article/20160405/BLOG01/160409926/plastics-help-lighten-the-load-for-us-troops