You really need to try some on to make sure you don't get any discomfort if your ear defenders squash your ear against the aid, or if you need to put them on in an uncomfortable position just to fit the aid within the muff itself. Failing that, it depends on your amount of hearing loss, but I have the Howard Leight Impact Sports and the volume does go higher than ambient so you may get away with taking your aids out while wearing them, but that depends on your prescription and if you have any extra programming in them such as tinnitus correction or stereo balancing to make up for a totally deaf ear etc.