I've used McMaster but they don't carry the Peltor. However, Grainger does carry 3M Peltor and carries the X5B behind the ear model. It's $47.45 at Grainger and

I've used McMaster but they don't carry the Peltor. However, Grainger does carry 3M Peltor and carries the X5B behind the ear model. It's $47.45 at Grainger and the X5A is $30.97 from Amazon delivered. Strange that it's not more available and less expensive. An alternative is the Peltor Optime 105 Behind-the-Head Earmuff which is 28 dB (vs 31 dB) and readily available at $23.99 from Amazon delivered. It also weighs slightly less, 11.4 oz vs 12.6 oz. zoro.com has the X5B for $40.83.