Locking button for refer access door

I need the small black button that twists 90 degrees to lock the outside access doors.  One of mine broke.

Anyone know of a convenient source?  Thanks

Boy I envy you if you actually have reefer access doors.  My louvers are secured by sheet metal screws.

My water heater door has a plastic ring, which is bound to fail soon.  I picked up an all-metal replacement at the local RV store.  

If all else fails, TM will mail you a couple for a small fee.

Hope this helps

Hubby used license plate nylon inserts and screws on ours.  Fit perfectly.  If these are not available at an auto supply house, try your friendly Ford dealer!  That's where hubby bought them.

thanks for the suggestions.  i bought a replacement at camping world today.