Round single cam toggle cylinders, i.e., small round cylinders, are double-opening cylinders that can be opened and closed with a key at each end of the door. The factory produces various sizes of brass cylinders for the Brazilian market, equipped with keyhole cylinders for the Brazilian market. The powder metallurgy cams and rotating inserts are made of high-strength materials FC-02-08 pressed and sintered and are characterized by their durability and resistance to wear and tear, which makes these cylinders suitable for entrance doors, aluminum doors, electrical cabinets, bedroom doors, electrician's rooms, plumbing and electrical rooms, public passages, stairways, and other applications. This lock cylinder is divided into: double-open, single-open, half-open, turn button double-open. Products according to the different needs of users can be equipped with anti-drilling, anti-dialing, anti-vibration function of the lock cylinder so that lawbreakers can not open the lock so that the user is more at ease.