The Smart is the new monofilament produced by the Belgian company Luxilon. I can’t remember so much hype generated by a string, result and merit of a very aggressive joint marketing campaign made by Luxilon / Wilson (the Smart is indeed sponsored as optimal string to be mounted on the Clash).
The string is composed of two materials combined in a single core of co-polyester circular section that has three polyamide cores clearly visible from the outside. The result is a “hybrid” string (Element style) that takes advantage of the control and spin characteristics typical of polyester with the elasticity and comfort guaranteed by nylon (polyamide).
The colouring is a “grey scale” where the light grey of the central core is “broken” by the dark grey of the polyamide cores. The effect produced is very similar to the two-tone strings that were in fashion some time ago (for example the Twice series of DoubleAR).
The Luxilon Smart is available in 1.25 mm sizes and, in the most competitive version, 1.30 mm.
The listing price for a reel of 12 meters is around 25 euros while for a reel of 200 meters is 320 euros. Obviously these prices are indicative and in shops you can find a few euros less.