Phenolic Sleeve / Tube is suitable for general electrical applications to assist in isolating bolts from flanges when galvanic corrossion is likely to occur.
Phenolic Sleeve is also not recommended for use in alkaline environments and is unaffected by most organis solvents.
Whilst Phenolic Sleeve (and washers) have been widely used over the years it does tend to be fragile and can become brittle and crack or break if under heavy bolt torque or not handled with care.
This is where Mylar Sleeve / Tube is now used in place of Phenolic Sleeve / Tube.
Available in all standard bolt sizes to suit both Imperial and Metric.