Just bought the Zero micro 30 feet as with residential I rarely go much higher but is this the right extension if I had to go to 40 feet?

Yes! This is the extension you would need to extend your XERO Micro Basic. 

Is it possible to use multiple extensions with one pole?

Without knowing which pole you are working with, this is a little difficult to answer. We do not typically recommend working with more than one extension set at a time based on its nesting design, but it also depends a lot on the pole you are working with. For example if you are working with a XERO Destroyer, you can add up to six extensions to reach its 90 ft capacity based on it's stiffness capabilities. 

Does this fit my 30ft XERO pro basic carbon fiber waterfed pole?

Great question! The XERO Pro Basic Add On Set would be a better option for your 30ft pole.

Does this fit on the M9 pole?

Hi there! The XERO M9 is a 6 section so you technically could add-on starting with a section 7 BUT the XERO M9 is a hybrid pole so it is not recommended to use extensions on it.

sir does this fit the zero carbon fiber 2.0 pole(New guy)thanks

The Universal extension is a #10 section. Thus, it fits onto any Xero Micro pole (9 section pole). To fit onto a Xero PRO pole: Use the Universal Kit. If you have a 30' PRO pole, use the 30' kit, a 40' PRO pole - 40' kit. After installing the kit onto Xero Pro poles and first extension, attach JUST the Universal Extension thereafter.

Does this fit the reach it mini? If so how many extensions can I add.

No, it does not. However, the Xero line has many options for poles, on which the Universal extensions will fit.

How much does this weight?

2lbs exactly.