Among the strings with modern fibers that are often used by beginners, archers are DACRON, due to their durability and stretch. With ordinary polyester material, Dacron has a strength of 50 lb or the equivalent of 22.5 kg per sheet (ply). Dacron strings have a relatively high stretch value (2.6%) which causes less wobble in the bow. Dacron strings are easy to maintain and can last relatively long. This brand produces some of the best custom replacement strings and cables for compound bows.
Other modern strings use liquid crystal polymer materials such as Kevlar and Vectran. This polymer material has a higher density and smaller diameter than Dacron. With a strength of 31.8 kg (70 lb) per strand and a stretch value of 0.8%, this string is capable of producing an arrow speed of approximately 2 meters/sec.
Ultra High Molecular Weight Polyethylene (UHMWPE), such as Spectra and Dyneema, has a strength of 45.5 kg (100 lb) per strand. Additionally, it has a 1% stretch rate. This string is lighter and faster than strings made of Kevlar, besides being more durable.
Sometimes modern strings are made from a composite fiber blend of Vectran and Dyneema, to take advantage of each material.
Later the classification of this type of string narrowed to only 2: Dacron and Fast Flight. Fast Flight is a string brand produced by Brownell.
Dacron is termed for strings that have a stretch value that is greater than Fast Flight.
While Fast Flight is termed for all types of modern string materials that have a stretch value that is smaller than Dacron.
Example of a string made from Dacron or equivalent:
Examples of strings made from Dyneema:
BCY DynaFLIGHT 97
Example of a Spectra string:
Brownell Fast Flight
BCY 652 Spectra
Example of a string made from a mixture of Dyneema and Vectran:
BCY 450 Plus