As the industry leader, Kwikset has provided trusted security for over 70 years and has become synonymous with security, peace of mind, style and innovation. The largest-selling deadbolt in America, the 600 series provides tough, effective protection at an affordable price. This single-cylinder deadbolt is operated by a key on the outside or a thumb turn on the inside. The complementary Antique Brass finish offers a warm feel with deep accents in the contours of the product.