I never really liked the look of the plastic LED's in certain areas of my pinball machines.  I work in automotive lighting and was working on a glass 194 type 12V LED and I requested some be made in 6.3V 555 type. (Why not?)   After a bit of trial and error in getting lamps made I think it fits the application.  I made sure the press dimension were accurate and the wire has the loop on the press to ensure it meets automotive standards.  Blends in for a stealth mode.  Nice color and great lumens.  No ugly plastics.  

This is the same size and shape as the old school glass 555 lamps in pinball machines. Glass press and looped wires for exact fit in the socket.  Designed for DC 6.3V operation.  I have tested these in my machines over the past year and they are 100% solid. 

These are PAINTED GLASS LED's and are directional in nature meaning they will only emit light in a left/right pattern.  Great for indicator lights to replace the original ones with nylon boots.  

They are not "non-ghosting" therefore you may see some dim bleeding in attract mode.   Not sure how to integrate the load resister into a glass lamp but who knows...