Which Ear Defenders
 

Well having just passed my Class One and being told that my hearing is low for a 35 yr old, I am aiming to get some proper ear defenders. The "in ear" type I have are pretty crap, especially when the APU is running (I fly 737).
Anyone know of a decent set and where to get them (I'm Gatwick based), but I suppose t'internet is best place. SNR levels seem to be quoted everywhere, but I don't know which is required, presumably highest is best. Do different types suit different frequencies, and so mean some are better suited to our environment?

Cheers for any advice,

PBR