Product Name : Fluorescence Oil for Leak Detection Why use fluorescent oils: Some air conditioners have been aged for a long time, and some accessories have aged and oxidized and there have been leakage. Small leaks can be difficult to detect. Usually it takes one week to three months for the refrigerant to leak out. It can't be checked out by normal means. Then you need to add fluorescent oil. NOTED: Due to the difference between different monitors, the picture may not reflect the actual color of the item, please understand. Thank you. I HOPE YOU'LL ENJOY SHOPPING TO MY STORE. WE WE'LL HAPPY TO SERVE YOU, THANK YOU AND GOD BLESS! Feedback (1)Please kindly leave us a positive feedback (5 stars) , if you are satisfied with our items.And you could share with your friends Thanks (2)Please contact us before leaving any negative feedback or open a dispute on Shopee. (3)Please give us the opportunity to resolve any problem.