This is a all brass near mint condition antique dog collar padlock.There isn't a mark on this lock not put there at the factory.There is a number one stamped into the shackle and looks like a dent in the photo,but under magnification,it is clearly a 1.There is still some lacquer protecting the back and bottom,but the lacquer is long gone from most of the rest of the lock.This lock has no name and the miniature cast bronze key is too small to stamp.The shackle spring is strong and jumps when the key is turned.The key is only 11/16 in. long.The lock is 1 3/16 in. tall.The photos with a dime and a dollar bill will give you some idea of scale.The round bull shackle is a rare design in miniature padlocks,The patina on this lock has taken decades to acquire and I won't clean it.This heart shape style was very popular in larger padlocks from a century ago.This tiny working antique has been in a drawer someplace for decades because there is no wear groove in the shackle,the best evidence that a lock was used on a moving animal.There were a very limited number of uses for such a miniature as this,especially from a time where people didn't even lock their doors.