Flic Allergen Free Fixer is an easy to use non-hardening fixer that is odorless and contains no ammonia or sulfur dioxide. Many people develop sensitivity to fixers after long term use. The culprits in this sensitivity have been identified as ammonia in rapid style fixers and sulfur dioxide in hypo style fixers. Flic Allergen Free Fixer contains no ammonia and has been formulated to not create sulfur dioxide when mixed. The use of Flic Low Odor Stop Bath is recommended to avoid the chances of a sulfur dioxide reaction that can occur with the use of acetic acid stop baths. Flic Allergen Free Fixer is a hypo style fixer and the use of Hypo-Clearing agent in the final wash is highly recommended in order to save water and time.