Ear defender suggestions

Have recently noticed that 3M peltor optime 3 has been amplify not noise cancel, sensory overload daily and want spare to replace 3M ones aside from provided ones by uni. Are there any that can block out overlapping conversation when wait for class for example since fed up being able hear sound rather than words especially during lectures due to sensory overload.

Is anyone available to give suggestions since unable to focus and concerned will effect class.