I recently tested Howard Leight's Impact Sport electronic ear muffs at a four-day shooting event where I fired handguns up to a ported, monstrously loud .460 S&W.
Through it all, the Impact Sports did a great job. The low-profile muffs were comfy to wear for long periods and allowed me to hear range commands and conversations with ease while the NRR 22-rated system shut out harmful blasts. Later, at my home range, a covered outdoor facility, I was working with a five-inch S&W .44 Magnum, and when I wasn't shooting I noticed an incessant ticking sound.
I thought maybe the muffs had developed a glitch, but then I spied a clock mounted on a post several firing points away--one I'd never noticed, or heard, before. I'm sold. Runs on AAA batteries and folds up compactly. $60.