The Handlock R15 40x40 brass security cylinder is a high-quality, durable product. Featuring a 10-piston system and protection against bumping, drilling, breaking, prying, extraction, and lockpicking, it guarantees a high level of security (level 4). Its dual-clutch system also allows you to leave another key inserted on the opposite side, offering greater convenience and versatility. It includes five plastic-headed key copies and is suitable for master keying. With a lifespan of over 100,000 cycles and compatibility with the JMA CI-21 (42705) key copy, this cylinder is an excellent option for those looking to effectively and durably protect their home or business.