I use these as well both in winter on snowmobile and summer on bike. IIRC I have the filters with the most attenuation installed.This is what I use:
EarPeace Motorcycle Ear Plugs – Noise Reduction and High Fidelity Hearing Protection for Motorsports (Standard, Black Case): Amazon.ca: Health & Personal CareEarPeace Motorcycle Ear Plugs – Noise Reduction and High Fidelity Hearing Protection for Motorsports (Standard, Black Case): Amazon.ca: Health & Personal Carewww.amazon.ca
Just make sure your ear canals are not wet prior to putting them on (for instance if you just showered before heading out for a ride / or used wet hands to put them on).
As long as its completely dry, they stay snug even when adjusting my helmet once strapped on (since I wear spectacles).
When riding on the highway, wind noise isnt as bad..while cruising I only hear vehicles around me and my engine/exhaust.
And yes - fire-engine/police sirens still penetrate it.
I've gone from Toronto to Ottawa and back (on the same day) using these and have had no issues.