We've all been there, you buy that great new shiny dog collar and then......you about throw it away over the frustration of getting your dogs tags off that fat D-Clip lol. Problem solved!  
 
For small dog collars that have the smaller D-Clip we recommend the Small Rub it clip.  
For any collar with a standard D-Clip which is usually found on most collars of 1 inch width, we'd recommend the medium or large. 
 
Small - 22mm
Medium - 27mm
Large - 32mm