Vallotton Locking Liner™ -This Is A Automatic D/A Knife. Internationally known knife designer Butch Vallotton developed this exceptional cutting tool to withstand the rigors of daily hard use. Vallotton has perfected the thumb stud pivot pin geometry making this the easiest, one-hand open and close model the discriminating buyer can buy. • Ambidexterous thumb stud • Massive pivot pin for strength • Internal Teflon washers for silky smooth action