Sorry for your inconvenient, I would like to inform you about fitting (SMC) that should not change to support tube air diameter 4 mm. I have confirmed with you that we will use diameter 3 mm. For questions about Fitting (SSP-44002) which show in schematic diagram (Page 26) It is fabricate part. By now, I have already requested 2D drawing from our supplier. If i get latest 2D drawing file. I will sent to you immediately.