Brian Robinson wrote: This is the port to inject a gas sample to around the wick from a bulb, it's called „the Garforth Injector“ after W.E.Garforth it's inventor, that's why GR6S. Garforth-Relighter-type6-Side injector. The phosphor bronze filter is to prevent and explosion inside the lamp from coming out. Many thanks Brian! (Picture right) > In die Öffnung der Schraube kann nachdem der Phosphor-Bronze-Filter entfernt wurde, mit einem Blasebalg Luft eingeblasen werden. Dies ist eine Gas-Testing-Lampe.