Not only will the Pro Volt hat from Electric give you more of the magnetic, hip style you so dearly crave, but it’s guaranteed to add an extra, ‘60s-style, onomatopoeic oomph to anything you do or say. Boom! S/M fits 6 3/4 - 7 1/4. L/XL fits 7 1/4 - 7 5/8. Sizes are approximate.