亚洲日韩乱码久久久久久,男人用嘴添女人下身免费视频,99久久精品国产免费,久久精品熟女

The company produces a series of Bunsen burner,it Is based on the requirements of various types of science laboratory, High quality materials, processed with advanced technology. Has heating efficient, uses safety but inexpensive advantages, Prices far below achieve equal quality levels imports product standards, that Is you choose Excellent ideal programs in Experimental equipment.
Bunsen burner （） is one of the common temperature heating tools in Science Laboratory. The tool is named after Robert •  William • Bunsen. The inventor is his assistant Peter Desdega. He first made a paragraph heater. And Faraday improved it in 1855. can burn gas safely.
Flame will not be back into the gas supply pipe. Fuel is usually coal gas or natural gas, propane gas, etc.
Product Features:
can be used to heating the non combustible objects or solution. It can be used to heating the object to the high temperature. Maximum temperature is close to 1900 ° C.
Because the heating temperature higher than the alcohol lamp, Therefore, the lamp must be used more heat-resistant material of metal. Also, because its fuel is gaseous at room temperature.Use should pay special attention to the safety of pipelines. used to pay attention to use of safety. You must first check whether all the switches in the closed state before use it. Sure all switches are closed state, Can open master switch.