A new style of official Wii wrist strap seems to be in circulation, this is now dubbed as the 'fourth version' which now includes a locking clip which holds the loop around your wrist.

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As you can see, this new strap includes a little locking clip, replacing the sliding clip of the previous models, which had a tendency to slide away from the player's wrist and loosen the strap. This new model would be the fourth incarnation of the strap; the first was the original model which tended to break, the second would be the replacement straps with the thicker connector to the remote, and the third was the replacement of the replacement that lacked the Nintendo and Wii branding.