Last month I did a review of the Zomm Wireless Leash Plus, a dongle that works with your iPhone and Bluetooth to find your keys or whatever else you happen to attach the dongle to. Recently, a BiKN (pronounced "beacon") iPhone case and tag showed up at my door from Treehouse Labs. BiKN works similarly to the Zomm, but has a few features that make it a vastly superior solution.
While the Zomm leash is useful, I found the use of the iPhone's Bluetooth to be somewhat of a drain on the battery. The BiKN resolves this issue by providing an external battery pack and built-in electronics. There's a micro-USB cable that is used to charge both the case / battery pack and the included BiKN tags. The tags just need to be charged every few weeks, and I found it convenient to just plug in the BiKN case every night to "top off" the iPhone and BiKN batteries. The iPhone is charged up first, and then the BiKN battery pack is charged. The BiKN battery pack cannot be used to power your iPhone, so it's not a substitute for an external battery pack like a Mophie Juice Pack.
The system is meant to be colorful, although my review setup was strictly black and white. When purchasing a BiKN system, you start by choosing the base color of black or white. Next, you select one of six different highlight colors (that was the white on my case). Then you select the base color for your tags (black or white), and finally pick a color for the highlight on the tag -- that's the part that has the loop you use to connect the tag to a keychain, a dog collar, your child's belt, or whatever else you need to find.