It's not hard to under or over-tighten a bolt when you are building a cabinet, let alone installing heavy hardware. So, hence, the SmartBolt. SmartBolts, designed for industrial and even medical applications, feature a simple color-coded indicator on their tops: If they're red, the bolt is loose. If they're green, nice job, everything's locked down. And if they're black, you may over-tightened things a bit, Mr. Look How Strong I Am. Each bolt also promise 20 years of durability (which actually seems a bit low for a lot of uses) as SmartBolts use simple fluid compression to measure and produce the chromatic indication in real time. That means there are no moving parts. Thoughts, Comments? It looks like they run between $16 and $24 per bolt, but that's for a sample of the bolts, I have no idea what I bulk order would be.