I just got off using the NoizeBarriers on the range for 3 classes back to back to back starting Friday. Prior on Wednesday I took the set out, freshly charged, for 2 hours on the range. Came back and kept it out of the charging pack 'cos I wanted to see if there would be some power drain. By Friday AM, I did a quick check before the class started and it was showing 90%. By end of Day 1, it was 60% with my keeping it on from 9 am to 4pm with a 45 min break from use for lunch. I put the pair back into the charging pack that night and repeated it again the next day, same results ending the day at 60%. By the end of day 3, the charging pack was showing 90%. I had some interference on the left side the first day and it would appear to be from not properly inserting it into my ear. I started with the smaller flanges but it was too deep inside for comfort so I swapped it out for the larger ones that first morning. Did not run in at HI, kept it a LO through out and did not have any issues both outdoors and in the shoot-house. Instructions/commands were clear, granted did not shoot anything other than pistol caliber in the shoot-house. Now my understanding is that Otto approached Ety about getting these particular model, spec'd out for themselves so I'm kind surprised to hear that Ety is also selling these.