New unopened 4 oz. bottle of Cargille Type-FF Immersion Oil for Fluorescence Microscopy.

Cargille Immersion Oils are the standard - the ones to compare with, the ones to compete against. Cargille Laboratories has consistently led in the development and standardization of immersion oil for over 42 years. Here is the record:

When the FDA set general purpose reagent criteria under the classification of In Vitro Diagnostics in the 1970's, Cargille Immersion Oils were already in full accord. To date, no other immersion oils meet the FDA criteria. Cargille Laboratories is known to microscopists as the source of both innovation and quality.

• Developed non-drying immersion oils (1940).
• First to standardize index and temperature values.
• Developed oils of different viscosities.
• Developed low fluorescence immersion oil (1940).
• First to print key optical properties on every bottle (1942).
• First to print full tables of optical and physical properties in Data Sheets (1946).
• First nondrying immersion oil adopted by major microscope manufacturers (AO, B&L)
• Cargille specifications adopted by U.S. Department of Defense.
• Developed the first very high viscosity oils for horizontal, inverted and projecting microscopes in cooperation with US Department of H.E.W. (1950).
• Developed the first PCB-free immersion oils (1971).
• Supplies oil to meet British immersion oil specifications.
• Collaborated with DIN and ISO committees in developing international standards and served as liaison with American microscope manufacturers.
• Provides modified formulas for special applications supported by Extended Properties Technical Bulletins.
• First to provide Material Safety Data Sheets to insure compliance with OSHA.
• First to establish a Refractive Index Laboratory with primary standard, computerized formulation and modeling capabilities for R&D, QC and Customer Service.
• First to modify immersion oil formulations for use with various instruments as calibration, mounting, contact and interface fluids in the fields of fiber optics, lasers, optometry, and optical engineering where special index, temperature, wavelength, viscosity, density and adsorption characteristics are required.
• First in worldwide distribution of immersion oils.
• Foremost in supplying US and foreign microscope manufacturers with "accessory" oils for new instruments.

The feature of this oil is its' low auto-fluorescence.  I have listed the specifications from the Cargille Site:

Fluorescence Microscopy Immersion Oils