英语翻译

英语翻译
a constant humidity of 65% +/- 5% without condensation.
再加一句：
The spectrophotometer should be located in a clean and conditioned environment
with a constant temperature of 20 degrees C +/- 2 degrees (68_F +/- 4_F) and
preferable with a constant humidity of 65% +/- 5% without condensation.