天天干夜夜爽-福利片在线观看-亚洲欧洲日韩-少妇精品无码一区二区三区-婷婷伊人综合中文字幕-一区二区视频在线播放-色婷婷精品-三级特黄-国产普通话bbwbbwbbw-怡红院成人av-日韩免费视频观看-中文字幕视频网站-亚洲乱乱-亚洲一区在线视频观看-久操社区

1. All stainless steel pipes are passivated by HNO3 and cleaned by methanol ultrasonic to ensure the use of chromatography;

2. Smooth inner surface ensures the best gas-liquid flow;

3. The annealed outer surface is bright and free of burrs, which is convenient for joint connection;