Despite the problem with under-helmet size, these are a superb pair of electronic ear defenders and offer what I think is the highest level of noise attenuation of the more tactical orientated Peltors with an SNR of 31. In addition to this, they come with a noise cancelling boom microphone and a 4 pin XLR connector for comms/PRR connectivity. With the right connectors, this could be set up to do hands free for a mobile phone, which was my plan, but with the lack of helmet-fit, is now sadly not going to happen.
The official Peltor link is here: http: ... gory_Id=97
£75 including tracked delivery to the address of your choice, or £70 collection from the Cambridge area.
Drop me a pm if you would like more photos or more information.