of the Kubotan can be used to create pain. A typical pain compliance technique involves seizing an attacker's wrist and sealing both hands around it with the length of the Kubotan laid across the radius bone. Downward squeezing pressure is applied to the bone to take down the attacker. Legality The Kubotan may appear as an innocuous key fob to the untrained eye. In some jurisdictions, however, it may be recognized and considered an offensive weapon. In the United States, there are few legal restrictions on Kubotans, with the notable exception that they are prohibited as carry-on items for air travelers. Whether a non-spiked Kubotan (i.e., a rod) is classed as an offensive weapon in the United Kingdom depends upon the circumstances of the case and is for a jury to decide. In April 2010 actor and entertainer Darren Day was found guilty of possessing an offensive weapon, namely a kubotan-style keyring, by a court in Edinburgh. Improvised versions of the Kubotan can be readily found and put to use. Because a Kubotan is just a rod made of a hard material, any restrictive regulation would most likely be ambiguous and undefined due to the ability for any common item to be used in a kubotan-like fashion. In this respect, the Kubotan can be substituted by everyday items such as hairbrushes, pens, markers, flashlights, small wooden dowels, and even electronic cigarettes. Metal pens (i.e., tactical pens) are sometimes marketed as substitutes for the Kubotan. Trademark Over time the registered name "Kubotan" (sometimes erroneously spelled or marketed as "Kubaton") has been eroded and genericized to include many knockoffs and imitations of the original design. Some incorporate spikes, tapered ends, and other modifications that were not part of the original invention. "Ninja" keychain weapons, often enhanced with blades, hidden darts, and tear gas, have also been marketed and sold as Kubotans. However, they are copycats and are more properly classified as generic self-defense keychain sticks (SDKS) or generic self-defense pocket weapons. The term 'pocket stick' is also sometimes used to classify such hand weapons. Books Takayuki Kubota & John G. Peters, Jr.: "Official Kubotan Techniques", Reliapon Police Products, 1981, Takayuki Kubota: Kubotan Keychain: Instrument of Attitude Adjustment, Dragon Books, 1985, Takayuki Kubota: Kubotan Keychain, Takayuki Kubota: Action Kubotan Keychain: An Aid in Self Defense: Key Chain – An Aid in Self Defense , Unique Publications, 1997, Bill and Becky Valentine: "Self Defense