Glass Viscometers Full range of Viscometer tubes for testing petroleum products. Available directly from the manufacturer. AllGlass Viscometers for Petroleum DIN Ubbelohde Viscometers U-Tube Reverse Flow Viscometers Cannon-Fenske Routine Viscometers Cannon-Fenske Opaque Viscometers Cannon-Ubbelohde Viscometers Suspended-Level Viscometers Suspended-Level, Shortened Form Viscometers Miniature Suspended-Level Viscometers U-Tube Viscometers Cannon Manning Semi-Micro Viscometers Miniature U-Tube Viscometers Zeitfuchs Cross-Arm Viscometers Shell Pattern Shortened Form Viscometers Shell Pattern Reverse Flow Viscometer Pinkevitch Viscometers ASTM Ubbelohde Viscometer