SLY is a brand of Valken Sports for their paintball protective mask product line and accessories. Valken is a leading manufacturer of paintball, airsoft, and outdoor products.
The Valken brand was created by two veterans of the sport, Tom Ziller and Brian O'Conner. They wanted to create a style of paintball uniform that would protect the player from injury while providing a high level of comfort.
As a matter of fact, Valken is a brand of protective gear that was developed with the purpose of helping people who were suffering from certain injuries that are suffered during paintball games.