The HamiltonBuhl SOP-HA2 Sack-O-Phones- 10 Pack of Hamilton HA2 Personal Headphones with Foam Ear Cushions. Sack-O-Phones packaging is a unique bag that doubles as a knap sack and holds 5 deluxe or 10 personal headphones. It's a great way to store headphones easily and economically, no need for costly plastic cases for storage. Sack-O-Phones Includes: (10) HA2 Personal Headphones with Foam Ear Cushions (1) Sack-O-Phone Carry Bag