Iris & push-fit coloured rings

Iris 0.5 - 3.0mm In an attractive, anti-reflective matt silver and blue finish Laser engraved indications Steel threaded connection - which for example enables the use of a diopter 5 external push-fit rubber rings which attach to the knurled ring in: Red, yellow, green, blue and black Designed to provide an illusory optical effect which ensures perfect eye alignment An extremely simple and inexpensive idea that gives an exceptional improvement