Purtroppo, questa descrizione non è stato tradotto in italiano, in modo da trovare a questo punto una descrizione inglese.
The LOA 21 Neutral Eyepiece is a match with one of the LOA 21 Deep Immersion 3D Pair. It matches the 21mm widefield eyepiece without the array.
So, remove the eyepiece with array (has the array threaded into the barrel and a bubble on the housing) and replace that with this Neutral.
Now you have TWO Neutrals in the Binotron27 and views of the Moon will be conventional and outstanding.
Viewing the Moon with the 3D Effect is fun and interesting, but for serious lunar viewing, the two Neutrals are what Denkmeier recommends.