In early 2016 American troops began receiving the latest version of the standard ACH combat helmet. The new LW-ACH (Lightweight Advanced Combat Helmet) is 10 percent lighter than the 1.5 kg (3.3 pound) ACH and has improved protection and comfort. Even before delivery of 105,000 LW-ACH helmets was completed (in late 2017) a lighter version of the ACH, the ACH Generation II was announced which is lighter still, has improved protection and easier to wear. The ACH Gen II will begin appearing in 2018 and it weighs about the same as the World War II M1 helmet. That last bit is what interests most troops as the weight of equipment troops are required to wear has been increasing since the 1980s and has reached the point where it is considered a health problem.
Source: Infantry: Lighter Is Much Better