The ND-Series has long been one of Schlage's best selling mechanical locks for good reason - it's tough, durable, Grade 1 rated and fits a wide variety of applications. Now we've made our trusted ND-Series lock even better by making it easier to install. We've added these enhancements because we know that a lock installed correctly the first time will last longer and perform better and the longer the lock lasts, the lower the cost of ownership over the life of the lock. The result: greater peace of mind that every door is safe and secured with a lock built to last.