What are "Shenayim Zeisim"?
Rashi: Two trees on which olives grow. Here it did not mention the two Tzanteros mentioned below (12). They are like troughs (in which olives are placed) and Adashim 1 of the olive-press. They stand by the olives, and the olives are automatically beaten into the Tzanteros. They are warmed there, like in the Ma'atan, and are pressed in the olivepress. The oil falls into the Tzanteros, and from there to the Gulah, then to the Mutzakos, then to the Neros. The Mutzakos [and Neros 2 ] were 49. This hints to the future ? "Ohr ha'Chamah Yihyeh Shiv'asayim k'Or Shiv'as ha'Yamim" (Yeshayah 30:26) ? 49 times the light of the day of Bereishis.
They are olives. (So imply Radak and Iyun Yakov Sanhedrin 24a).
Rashi (Avodah Zarah 75a): This is the trough. Tosfos (Nidah 65a DH ha'Dapin) ? it is a round Kli that weighs down on the olives. (Here also Rashi implies that it is not the trough itself! Perhaps he retracted. ? PF)
There are seven Neros, and 49 Mutzakos, for Rashi (2) said that there are seven for each Ner! Perhaps the words 'and Neros' are a printing mistake; they should be deleted. (PF)
To what does "Aleha" refer?
Radak: It means on (near) the Menorah or on the Gulah. In either case, the meaning is the same.
Malbim: They were on the Menorah, near the Gulah.
Why does it say "Echad mi'Ymin ha'Gulah v'Echad Al Smolah"?
Radak: Al Smolah is like mi'Smolah. Here it says that they were right and left of the Gulah; below (11), it says right and left of the Menorah. These are the same.