S-645 – Knoblochs Protex Pre-Soak is a water-soluble compound that is made for the protection of hair, fur and feathers from moth and other insect damage. It also cleans and conditions the hair. This concentrated product is used as the last rinse of the tanning process and in the rehydration bath prior to mounting. Use one ounce to 1 gallon of water. Van Dyke’s offers a variety of Knoblochs Chemicals. Sold by the quarts.