Carlsbad, Calif. — Linear LLC has upgraded its standalone AK series of access entry keypads by adding new programming features. The new AK-11, AK-21W and AK-31 will replace the older AK-1, AK-2W and ...

We independently review everything we recommend. When you buy through our links, we may earn a commission. Learn more› By Doug Mahoney Doug Mahoney is a writer covering home-improvement topics, ...