There are lots of options for lapel pin backs and some are better suited to different situations than others. Below we've discussed each of the options. 
 

• Military clutch back, also called butterfly clutch.  The military clutch is the standard lapel pin back throughout the world.  It is a small round device with a flat back with a hole in the center.  The "butterfly" refers to the thin metal inner part of the clutch that is shaped like butterfly wings.  Press the wings together and the clutch releases from the nail.  
• Deluxe clutch back.  The deluxe clutch back is a substantially more robust version of the military clutch.  It operates on the same principle by gripping the nail of the pin.  However, there are two important differences between the military clutch and the deluxe clutch.  First the deluxe clutch is made of much thicker material and has a higher perceived value.  That is why it is the standard on higher end jewelry.  Second, the deluxe clutch operates by pulling up on the top in order to release the clutch.  The deluxe clutch comes in two varieties flat head and round head.
• Rubber or PVC clutch back.  The rubber or pvc clutch back is a non-mechanical clutch - there are no moving parts.  It operates by taking advantage of the flexible nature of the material.  It is shaped like a military clutch but the hole in the center is smaller than the diameter of the pins nail.  Press it over the nail and the material expands - gripping the nail and holding the pin in place
• Joint and catch / safety pin backs.  These pin backs are popular on brooches and for larger pieces in general.  A long metal pointed pin is affixed on a hinge at one end of the pin.  At the other end is a catch that locks the pin in place.  As noted these are only appropriate for larger pins because they are extremely difficult to close on smaller pieces.  
• Magnetic pin backs.  Magnetic pin backs have become very popular.  The biggest factor driving their popularity is that they alleviate the need to put a hole in a garment.  One critical thing to remember about magnets, they only stick to steel - not brass or zinc or pewter (common materials used in pin-making).  When a pin is not made from steel, a steel plate is affixed to the back of the pin.  If the pin is made from steel, then the magnet will stick directly to the pin.  Typically the magnet is a strong neodymium magnet.  This type of magnet is fairly expensive and typically adds about a dollar or more to the cost of a pin.   One potential downside of magnet backs - if you brush up against something or catch the pin on something, it will pull off - and the magnet will slide down inside your garment.  
• Pin-Locks - Pin-Locks were developed by StockPins.com as a way to semi-permanently install a pin.  They are very popular with pin collectors around the world.  They consist of a small diameter metal cylinder with a hole in the center.  On the side of the cylinder is a set screw.  The pin-lock is placed over the nail and the set screw is tightened - locking the pin-lock in place.  Pin-Locks are sold 12 to a bag and come with an allen wrench. 

I hope you've found this helpful.  Of course, if you have any questions please don't hesitate to give me a call at 800-856-0595 and I'll be happy to go over them with you

Thanks

Pinonda Lapel