Ch?n ch?t li?u tem nhãn: Ch?t li?u tem nhãn c?n ???c l?a ch?n phù h?p v?i lo?i s?n ph?m và m?c ?ích s? d?ng.Chilly finger-A long copper rod extending alongside The within with the electron column. When its reservoir is kept full of liquid nitrogen, the rod draws in contaminants That may normally degrade the chamber's vacuum.D?a vào m?c ?ích,