TIHK, originators of the Tiny Inconspicuous Handcuff Key, just released the details of an upgrade to their namesake product. The new TIHK HK2 retains the small size, non-ferrous construction, and integral clip that made the original TIHK so great.
However, the HK2 also boasts two major improvements over the original. Teeth have been added under the clip to ensure that it is stays in place. The integrated clip and it’s ability to hide the TIHK in places that make sense (like behind your back on a belt loop) is part of what made the original TIHK great so improving this feature makes good sense.
The second improvement comes in the form of some changes to the key portion of the TIHK that allow it to work more easily with a wider variety of cuffs. TIHK specifically references the HK2 working better with Peerless style cuffs. My original TIHKs can be made to work with the ASP cuffs but it was difficult. It will be interesting to see if the new HK2 version offers an improvement in function with ASP cuffs.