FOR SALE IS ONE PACKAGE CONTAINING 6 LIGHT JEWELS BY SPARKY'S ROUNDHOUSE. THE SIZE OF THIS ITEM IS A NOMINAL 15/64" OR NOMINAL 6MM AND IS NEW IN THE LABELED  PACKAGE. THIS JEWEL IS A FLAT BACK JEWEL THAT HAS NO POINT ON THE BACK SIDE. EVER SEE AN UNPOWERED LOCOMOTIVE OR TRAIN CAR THAT LOOKED LIKE IT HAD LIGHTS POWERED UP, WELL THAT WAS MOST LIKELY A JEWEL YOU SAW COLLECTING AND REFLECTING ROOM LIGHT TOO SIMULATE A LIGHT BULB BEING ON. IN YEARS PAST IN THE TRAIN HOBBY THE USE OF RHINESTONE JEWELS WAS VERY POPULAR. THE SIZES OF THESE  MAY BE ROUNDED UP TO THE NEAREST MM SO VERIFY BY THE PICTURES THAT THIS IS THE RIGHT SIZE ITEM YOU NEED FOR YOUR APPLICATION. I HAVE INCLUDED PICTURES OF THE JEWEL BEING MEASURED BY CALIPERS TO SHOW FRACTIONAL INCH MEASUREMENTS AS WELL AS METRIC MEASUREMENTS. OLD BRANDS LIKE MANTUA, TYCO, ROUNDHOUSE, ATHEARN, REVEL, BOWSER VARNEY AND OTHERS ARE FAMOUS FOR THEIR USE OF JEWELS TO  SIMULATE LIGHTS ON LOCOMOTIVES AND ROLLING STOCK.     

VERIFY THIS IS THE PART NEEDED FOR YOUR TRAIN BEFORE YOU MAKE PURCHASE.