Multi - purpose guide eye in anodised aluminium with Teflon coating, outer diameter 20mm, inner diameter 8mm. - - Multi - purpose guide eye Made from anodised aluminium with a Teflon coating. 20mm outer diameter, 8mm inner diameter. Suitable for barber - holers, lazy jacks, etc. Colours: black, orange, blue or grey. ALUMINIUM THIMBLE A..87 - 20 - Technical documents can be downloaded here