Q1: Is the compass/reticule displayed in the binoculars all the time, or can it be turned off so the binoculars can be used without it as binoculars without the compass/recticule?

A: All the time.

Q2: Measuring Distance, Height and angle. Please can you confirm in the equation L=H/MILS x 1000, what is MILS?? Miles? millimeters? Thank you.

A: The MILS stands for mil dots. The number on the reticle vertically is that.

Q3: Do these float?

A: i am sorry but no they do not float, there are however Marine neck straps available that will make the binocular float.

Q4: i watch airliners take off and land from my house which is between several major airports. how well do these binoculas pick up at 28 to 30 thousand feet? my opera glasses can pick up at about 15 thousand feet and even read the airline names but they are old and have no sun filters. can i expect better from these binoculas?

A: You can definitely expect better as a standard opera glass is only 3x the naked eye while these are 7x though there is not a sun filter that I know of.

Q5: what % of light gathering do the zhumell 7by 50s marine binoculars with compass have

A: IF you're referring to light transmission, that runs about 92%. As far as light-gathering ability is concerned, these binoculars have a "twilight factor" of 18.7, which means in general that they will perform quite well in low-light conditions.

Q6: what is binoculars made out of

A: Zhumell 7x50 Marine binoculars with compass and reticle have an aluminum alloy body.