Just to double check, this is the final requirement, isn't it?

我double check（再次确认）一下 这个需求不改了是吧

Double check your smoke alarms.

检查两遍你家里的烟雾报警器。

Here's some things to double check.

以下是一些需要仔细检查的东西。

Please double check it.

请再核实一下。

You'd better make a double check with your answer.

你最好再核对一下答案。

So just double check to make sure that you have the right recipient.

只要再检查一遍，确保收信人是对的就可以了。