The LOGIC heads are the perfect solution for the effective Scandinavian-style of fly fishing. The LOGIC heads range from 7.0 meters to 10.5 meters, in 9 different weights and with incredibly small loops. Note; The density, weight and length are printed on the color code of all Logic lines. Salmologic lines come in many different densities and lengths. Together with salmologic leaders and running lines, they will open up endless possibilities for you in presenting the fly, no matter how challenging your river might be when it comes to depth, current or natural hindrances.