Silverhook Chainsaw oil has been formulated using high viscosity Base oils and special tacky modifiers which help reduce wear on all chains bladesfits excellent Non fling characteristics> good oxidation stability> good low temperature stabilityiso 100 is a measure of viscosity of oils at operating temperatures. Iso 100 chains oil is ideal for home use where the chains blade will not see extended continuous use, thus reaching a lower operating temperature. for professional use or for use with chainsaws that will See extended use A higher ISO oil would be beneficial – Silverhook offers an ISO 150 chains oil which offers a higher viscosity.