umashankarThey should fit in the Slappa SL-HP-99. I just bought 2 of them I was so impressed with it. It easily fits Fostex TH-X00 series headphones. Beyer Dynamic DT880 and DT990 swim inside it's so roomy. Also Audio Technica ATH A and AD series headphones with the wing adjustment headband and the HUGE cups fit this case and even the smaller SL-HP-07 case from Slappa. Both available on Amazon for $20. If I decide to get the HE4XX I'll immediately grab another one of these cases.