The weapon operator search and locate the target using a periscope optical sight (7km range) in day light, or a thermal imager at night or in bad weather conditions.

武器操作员在白天亮光下使用一个潜望镜白光瞄准镜（7公里范围）或在不良天气条件或夜间使用热成像去搜寻和定位目标。

youdao

For me, one of the biggest frustrations of ME2 was constantly running out of thermal clips on my preferred weapon in the middle of a firefight, and then having to shift to another weapon.

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